In order to realize the large scale and high parallel perfonnance of database cluster system, the techniques of cluster are applied to the database system，and a comnon middleware system with high paral- lelism is proposed based on share一nothing database cluster, which provides the architecture of single sys- tem image for the clients and realizes the collaboration and parallel execution in the database cluster by us- ing the techniques of the meta data management, the multi一thread mechanism and the parallel transaction pre- processing，and it is well suitable for the high performance requirement of the OLTP commercial ap- plication and has an ideal price/performance ratio. The database cluster system not only keeps the auton+ my of the local database sites but also improves the parallel performance of the database cluster system and solves the performance bottleneck of large database system.