This paper studied on the key technology of synchronous modeling- face finder and geometry index and flexible and rigid solve on platform of NX 6 and windows. This technology supports modeling by identify a range of input faces and geometric conditions of a group faces to search, find and choose faces by face finder, and solving surface-related acts of movement at the same time. While the technology was theoretical analyzed, the practical examples was also employed to testify the efficiency of the technology. Parametric or non-parametric 3D models were modified by the operation of face moving, face copying or face choosing, and face transforming to revise the position relationship among faces. Thus the topology structure of the model is altered, and product model design and modification work is completed efficiently.