The companies' risk taking significantly affects the credit rating, thereby affecting the corporate bond issuance eligibility and financing costs, so the companies issuing bonds have the motive for the adjustment to risk taking strategy based on rating. This paper examines the changes in risk taking before the initial credit rating, and tests the influence of risk taking on the initial credit rating and its market reaction. The empirical results show that, before obtaining the initial credit rating, a firm's risk taking continues to decline, and then rises slowly, indicating that the companies adjust risk taking to cater to the rating demand; risk taking and the main credit rating are negatively correlated; through the intermediary effect of credit rating, the risk taking is significantly positively correlated with the costs of bond financing. The companies can obtain the ideal main credit rating by tactfully adjusting the risk taking, and thereby achieve effective saving of the financing costs.