Battlefield environment simulation plays an important role in battle and training simulation systems. As part of the virtual battlefield environment, CGF is the critical technique of virtual battlefield environment. In order to provide effective support of tactical training, combat missions training and tactics research for the flight simulation training system, a CGF system is developed through the CGF entity framework of VR_Forces based on the Object Parameters Database making use of the CGF entity modeling based on the component factory mechanism. The CGF system mainly generates enemy forces, provides with realistic simulation campaign environment, and better meets the training requirement of the simulation training system.