Abstract: The concept of process slicing in business process execution language(BPEL) and related static slicing algorithm are proposed.Given an activity and variables referenced by this activity(called slicing criterion),one can analyze and obtain the process segment which influences the slicing criterion during process slicing.Based on the slicing criterion,a BPEL control flow graph(BCFG) and related activity dependency graph(ADG) are constructed respectively,and then the sequence of activity(process segment) is identified through the analysis of the ADG.The result of such analysis has been proved valuable in process analysis,optimization and parallelization.