Abstract: The product design quality is the integration of product major, auxiliary functions and product constructional, operating, technological performances. The assignment of weight of those functions and performances is studied. An AHP model is developed for product design quality to form a pairwise comparison matrix. Based on the pairwise comparison, the assignment of weight of each and all functions/performances as above is determined in product design quality through hierarchical ranking and consistency test. Taking a vibrating screen as example, the weight of each and all functions/performances in product design quality are calculated, thus verifying the feasibility/effectiveness of the AHP-based assignment of weight in product design quality.