Abstract: The design transaction management is one of the critical technologies of EDBMS.Due to the complexity,the controlled cooperative work,the long duration of design processes,and the enormous number of objects involved,a suitable transaction model for the designers to access the EDB must be satisfied by EDBMS.A design transaction model under the environment of the CAD/CAM is discussed,which has a nested transaction structure and a mechanism of object delegation.A main objective of this model is to support cooperative work in the CAD/CAM environment.