Abstract:The Guide-weight criterion is a rational criterion for structural optimization, which strictly derived from Kuhn-Tucker extremum condition. The criterion is expressed as: in an optimum structure, the weight of a component group should be proportionally distributed by its Guide-weight. Guide-weight criterion is clear in meaning, simple in form and easy to employ. Guide-weight criterion had conquered drawback of virtual work criterion method that neglecting derivative of load changing with variable change. In many application examples, it is shown that Guide-weight criterion took advantages of fast convergence and excellent result. During the iterative computations in structural optimization, it is the function of Guide-weight criterion to guide rational distribution of design resources, such as structure weight or cost etc., to cause this distribution to achieve an optimal status that the weights of component groups are proportional to their Guide-weights. The mathematical meaning and mechanical meaning of Guide-weight and Guide-weight criterion are explained, rationality of the Guide-weight criterion and the supervise sense of Guide-weight criterion for optimization iterative are discussed, and an index measuring the optimization degree of structures is proposed.