Abstract: Reducing the cost of atomic commit protocol always is an important research topic. Presented in this paper is a new log mechanism, named cooperating memory cached log mechanism （CMCL）. Now, transmitting data through high-speed network is faster than writing data to hard disk. So when needing forcibly flush log to disk, the log is transmitted to other computer and saved in memory for reducing data lost risk, and the log needn’t write to disk immediately. The principle of CMCL is given and used to improve two-phase commit protocol. Finally, the performance is analyzed and compared.