The Business Process Execution Language (BPEL) is now a de facto standard for specifying and executing business process for web service composition and orchestration. As more and more web services are composed using BPEL, tuning these compositions and gain better performance becomes increasingly important. This paper presents our approach for optimizing the BPEL process and introduces OptBPEL, a tool for performance optimization of BPEL process. The approach starts from the optimization of synchronization structure concerning link in BPEL. After that, some concurrency analysis techniques are applied to obtain further performance improvement. Finally, we give some experiments and prove the efficiency of these optimization algorithms used in OptBPEL.