Abstract: By using method of condensation of degree of freedom, a condensation method of degree of freedom for parts and components is proposed, and base on this method, a new support position layout optimization method in printed circuit board structure is built up. This optimization method makes computation amount reduce greatly and reuse the condensation model easily. Additionally, by using genetic algorithm method and second- develop technique, the solving software is developed. Optimization examples show the optimization method is feasible and effective for engineering projects.