Abstract: Workflow management technology plays an important role in business process re engineering （BPR） and business process automation. It provides a set of tools to model, analysize, simulate and realize business process. A workflow management system-AutoFlow based on the standard proposed by Workflow Management Coalition is developed. The modeling method is the kernel in the AutoFlow. A WfPN（Workflow Petri Net）model based on Petri net is presented as a kind of modeling theory, and to illustrate how to map the real business to WfPN model. WfPN model may act as a powerful modeling tool in the workflow management system to realize the business process automation and the BPR.