Abstract: While workflow technology is increasingly used to manage complex processes in scientific and business field,the enhancements to Web service capabilities are rectuired. The Petri net based workflow model has limitations that could not depict the course of state transition or the event happened at the moment of state transition. An ECA-rule based Web Service workflow model was proposed. The process instances of the model is driven by events, Which not only ensure workflow to run and monitor correctly but also sustain dynamic modification at runtime.

Key words: Workflow, ECA rules, Web service