Taking non-financial companies of China from 2008 to 2012 as a sample, using Cscore to indicate accounting conservatism for companies and Fangang index to measure law risk, we construct a regression model and consider the “reverse causality” in the robustness analysis in order to study accounting conservatism, law risk effects on audit fee and the adjustment effect of law. The results show accounting conservatism can decrease auditor requirement on auditing fee. And law risk increases auditing fee, where there is high risk in lawsuits, the auditing fee will be higher. Where there is law risk, there is a stronger negative correlation between accounting conservatism and auditing fee, which suggests that the accounting conservatism can make a bigger effect on audit fee decrease.