Using data of Chinese A share listed companies during 2004 2011, this paper adopts cash flow sensitivity of cash holding model (Almeida, 2004) to investigate the influence of monetary policy and accounting conservatism on financial constraints, and to investigate the difference impact of the two mechanism from the property right perspective. Firstly, this paper finds that tight monetary policy aggravates the firms financial constraints, while the accounting conservatism releases the firms financial constraints; secondly, accounting conservatism helps weaken the negative effect of tight monetary policy; finally, the negative influence of tight monetary policy is more significant on non state owned enterprises, and the alleviating effect of accounting conservatism is more significant on non state owned enterprises.