SPEM(software process engineering metamodel)is the standard metamodel put forward by OMG (object management group)and widely accepted in industry.However,its model enactment is still at the early stage. In this paper,software process is viewed as a specialization of the more general kind of process known as workflow. SPEM2XPDL is presented as a software process enactment approach based on the model transformation.The well-defined mapping rules from SPEM to XPDL(XML process definition language)metamodels are provided and the corresponding transformation algorithm and engine are developed.This approach is implemented in the SoftPM project.After transformed to XPDL format,the SPEM models are successfully enacted by Shark,a famous XPDL engine.