針對當前工作流模型沒有明顯的時間約束以及缺乏對復雜工作流系統支持的現狀，對經典Petri 網在時間和層次方面進行擴展，提出了一個時間和層次擴充的THEWF-Net 工作
流模型。給出了該工作流模型的構建算法，并采用此算法對辦公自動化系統中的產品開發流程和改造舊產品流程進行了建模，最后以實例對該工作流模型的正確性進行了驗證。
關鍵詞工作流；工作流模型；Petri 網
Abstract：At present the workflow model is short of time constraint and can’t support complex workflow systems, so the classical Petri-Net is extended in time and hierarchy in this paper. And based on the above extension a Time-Extended and Hierarchy-Extended Workflow-Net model is given. At the same time the construction algorithm of the model is also put forward in this paper. The algorithm is applied to model the new production-developed process and the old production-reconstructed process. Finally the correctness of the THEWF-Net model is validated.
Key words： workflow; workflow model; Petri-Net