Abstract Cooperative pattern design is one of the typical applications of Computer Supported Cooperative Work(CSCW ),and the concurrent accesses and controls of cooperadve data are the central problem.In this paper,based on an Internei-based cooperative pattern design protocol system(CoDesign)developed by the authors,an idea of treating the data operations by the users as the operations of database transaction processing in the cooperative process,and formally research the transaction model of describing the operational behavior.This technology can solve the cooperative data procesing problem effectively.