Minority shareholders are one of the important stakeholders in corporate governance. Owing to the dual principal-agent problem, minority shareholders may face the moral hazard from managers, the tunneling of controlling shareholders and even suffer from the collusion between managers and controlling shareholders. Therefore, Chinese government has committed to issuing a series of laws and regulations since 2004 to create a good environment for online voting and trading to protect the interests of small investors, which actively encourages minority shareholders to participate in corporate governance in a variety of ways. This reflects that governance participation of minority shareholders is in a great need in reality. However, in the traditional environment, due to the high cost of information acquisition and governance, minority shareholders often take a free rider attitude to their legal governance rights （Grossman& Hart, 1980）. But with the rapid development of the internet environment, the traditional corporate governance has changed greatly, that is, minority shareholders as positive governance participators have emerged, corporate governance cost is significantly reduced, the new means of governance has appeared and information disclosure is strengthened （Li Weian, 2014）. Therefore, the governance effect and mechanisms realized by minority shareholders in the internet era are worthy of further discussion and examination.　　In recent years, some scholars have attempted some pioneering exploration and accumulated valuable foundation for further research. Firstly, from the research perspective, most of the prior researches consider the governance effect of online voting either by hand （Chen Z, 2010; Kong Dongmin et al., 2013） or with feet （Bharath S. T., 2013） rather than both of them. As to this, we take the two behaviors in a same research framework and analyze their influences on the two types of agency costs. Secondly, from the research content, foreign scholars have different opinions on the governance role of minority shareholders （Bebchuk, 2005; Listokin, 2010）, while domestic scholars generally hold positive attitude towards the governance role of minority shareholders which has a continuing trend with the development of the internet （Jia Yingdan, 2015; Kong Dongmin et al., 2013; Yang Jing et al., 2017）. However, most of the prior researches have focused on the test of the governance role rather than mechanisms. In this regard, based on the test results of the two kinds of agency cost inhibited by the governance behaviors of minority shareholders, we further conduct a grouping test on the two subsamples of state-owned and non-state-owned enterprises in order to reveal the governance mechanism. Thirdly, from the research data, the online voting data of shareholders after 2009 are not available publicly, which causes the research work to be fragmented and stagnant. Prior domestic research results may not suit the new era with the rapid development of the internet （Kong Dongmin et al., 2013）, or remain to be tested in large samples（Zhang Weiwei, 2015; Zheng Xiutian& Xu Yongbin, 2013）. In this regard, we collect the data of the number of shareholders attending the online meetings and then design an index as the proxy variable of voting by hand of minority shareholders, which to some extent keeps the continuity of data and indicators and makes up for the deficiency that the latest online voting data is unavailable. 　　Therefore, based on the prior research, in the context of the new internet environment and dual principal-agent relationship, we study the effect of governance behaviors of minority shareholders on the agency cost, taking Chinese A-share listed companies between 2009 and 2015 as the sample. Through the construction of regression models on the above problems, the empirical research results show that governance behaviors of minority shareholders only have significantly negative effects on the manager agency cost rather than the expropriation of large shareholders. Based on the results above, we further make a group regression according to the ownership of enterprises to compare the influence of governance behavior of minority shareholders on the agency cost, which shows the mechanisms through governance behaviors decrease agency cost. The regression results show that voting by hand improves managers’ agency ability through administrative intervention mechanism, while voting with feet restricts managers’ perks through the market pressure mechanism.　　Our study provides strong empirical evidence for confirming the minority shareholders as new governance participators in the context of the new internet era, which to a certain extent enriches the theory of corporate governance; it also provides theoretical support and motivation of perfecting the online voting system and trading platform for the securities regulators and new ideas of improving the corporate governance environment for the company management. 　　There are four important contributions made by our study. Firstly, discussing the governance effect of minority shareholders with voting by hand and voting with feet in the same framework can reveal the governance role of minority shareholders comprehensively and objectively. Secondly, the conclusion of the study confirms the governance constraint of minority shareholders on agency costs of managers, which is contrary to the implicit assumptions of traditional corporate governance research. Thirdly, the conclusion of the study also reveals governance mechanisms of the minority shareholders, which provides a theoretical basis for SOEs to make or vote on share transfer schemes under the background of mixed ownership reform. Finally, constructing the index evaluating minority shareholders’ voting behavior can compensate for the lack of data of online voting, which makes the feasibility for the continuity of related research work.