This paper selects Beijing,Shanghai,Guangdong and Hubei carbon market close price from the market set up to March 31,2017,examines the weak-form carbon trading market efficiency,analyzes the daily returns data which uses an autoregressive process to eliminate the thin trading effect,based on the four tests which the credibility gradually increased.The results show that the carbon markets in china are thin markets;the information of carbon price is pile and the information transparency is poor;with high inve...