Abstract: It is difficult to guarantee correctness of workflow model control structure by artificial, when case semantic of business rules in workflow model changes more complicated. Methods of construction automatically are less. At first well block structured control structure was introduced,which has lots of useful properties in model soundness. I3y ana- lyzing topology of blocks in workflow models, branch and merge control structures and syntax rules they should follow were defined respectively. Algorithms of branch control structure were proposed according to semantics of business rule. Then based on this, algorithms of merge ones were proposed using all branch weights. Finally a practical example was given to verify the constructing process of correct block structure. This method is independent of specific modeling method, so that has three advantages, complete commonality, modeling-independent and wide applicability.

Key words: Workflow model, Control structure, I31ock structure