Location is a commonly used tolerance control criteria in the geometric dimensioning and tolerancing area. This tolerance is of special importance to the high precision assembly industry. The control of tolerance in design, manufacturing, and assembly is vital to preserving the functionality of products, the validity of assembly plans, and the optimality of the tolerance and equipment assignment. This research develops a computer-aided assembly process tolerance control system to help the assembly process planner to verify the tentative assembly process plan. Also, a weighted assembly process decision support module is incorporated to help adjusting the tolerance allocation as well as the selection of appropriate assembly procedures. The optimality of the resultant assembly plan is ensured based on a minimum cost model by using the mixed integer programming technique.