In order to solve the problem of the lack of scientific and quantifiable evaluation method for the structural optimization degree and operation convenience of the sling product, the lean design theory and the lean design tool method are proposed. The structural characteristics and service operation requirements of army large ammunition were analyzed, the requirements of army large ammunition universal spreader were defined, and the evaluation method of army large ammunition universal spreader was put forward, which realized the quantitative evaluation of spreader product structure optimization degree and operation convenience. The results show that the method has a certain guiding significance to clarify the research and development needs of the sling products, provides a quantitative comparison basis for the optimization design of the sling products, and also has a reference value for the establishment of evaluation index and optimization design guidance of similar products.