A comparative study is conducted in this paper to investigate,under compulsory and voluntary disclosure mechanisms,if there are differences in the quality of carbon information between enterprises and if there are differences in investors'interpretation of carbon information?The empirical result shows that enterprises,under compulsory disclosure mechanism,tend to disclose carbon information of higher quality,which does not seem to provide useful incremental information for investors.On the other hand, voluntary carbon disclosure is referred by investors,as the value of enterprises is closely related to information quality under voluntary disclosure mechanism.This result agrees with the signal theory.In addition,the influence of political connection on enterprises'carbon disclosure is also studied.It is found that this influence is positive at first and then becomes negative.Finally,suggestions are put forward to standardize enterprises'carbon disclosure and increase market efficiency.