By the unbalanced panel data from 1999 to 2008 of Chinese listed companies, we use dynamics panel data to find out the reasons for debt conservatism. The results show that the financial conservatism is highly positively related to future investment; however it is not significantly related to product market competition. Meanwhile, the dividend is helpful to corporate investment and the corporate size has positive impact on investment. All these testify that debt conservatism policy is employed for future investing, rather than caused by market competition.