To solve the interweaving of business logic of process and application logic of business tool, the concept of application level component (ALC) is introduced based on which the workflow integration framework is put forward. In the framework, ALC acting as business tool is required to conform to specific interface specification. Finally, a three-layer activity model is proposed which not only realizes the separation of the business logic of process and the application logic of ALC but also simplifies the description and execution of workflow.