The model based digital definition technolgy integrates feature information including 3D size tolerance annotation feature information including 3D size tolerance annotation and manufacturing requirement  annotation on the basis of 3D product model.Without 2D drawing

the model based defintion can realize the description and sharing of product features

meet the requirement for dircet transfer of information syetem

and manage information by classification. The aplication status of model based on definition technology is analized according tothe subcontract production of B787aircraft in China.