Using the current commonly used operator priority method, introduces a common expression of the calculation process, and one of the key issues, operator precedence matrix design and implementation.

Combined with method based on order and serial schedule generation scheme and multi-project task list, the gotten scheduling scheme can meet the project schedule constraints of precedence relations.

Thus, a method with intercrossed concurrent and increasingly iterative perfection for the description of precedence relation in the dynamic CAD design has been worked out.