The effects of political connections brought by private entrepreneurs' participation in politics are widely concerned, but it needs to be further proved that whether the state ownership in private-owned enterprises also has the effect of political connections. Based on private-controlled listed companies in China, this paper studies the effect of state ownership in private-owned enterprises as a political connection mechanism. The results show that state ownership can help private-owned enterprises to acquire more economic resources and development opportunities owing to its systematic connections with the governments, which works as a reputation guarantee for the development of private-owned enterprises. Meanwhile, these financing convenience and economic resources further improve the private-owned firms' performance. It adds to the research references in the fields of enterprises' political connections, and provides a new perspective for fully understanding the effects of political connections in the period of China's economic transformation.