Abstract: In order to solve the problem of low description ability，expansibility，flexibility，encapsulation existed in current of workflow management systems，a new modeling method based on the implementation of the whole process of task (IWPT) in workflow，feedback mechanism and encapsulation thinking is put forward. And according to the given example of product development procedure，the significant advantage of this method will be found in enhancing description ability，improving system expanding and flexibility. The proposed method has important value in designing and developing workflow management systems with high reliability，flexibility，adaptability and replanting.

Key words: Encapsulation, Expansibility Flexibility, Implementation of whole process of task Workflow model