Condition Assessment and Application for Mechanical Structure Based on Stochastic-fuzzy Method HU Xiao yan (Department of Logistics Engineering, WUT, Wuhan 430063, China)Using the condition indexes and index weights to indicate the technical features of the mechanical structure. There are two kinds of the condition indexes and index weights: descriptive and numerical. The values of the condition indexes and index weights in different cases can be determined by the fuzzy and the stochastic method. By comprehensive considering of the technical features of the mechanical structure the corresponding deterioration norm can be gotten. Based on the deterioration norm, the technical cases of the mechanical structure are classified and the assessment result for the safety of the mechanical structure is obtained. The application example indicates that this method is feasible.mechanical structure; safety assessment; fuzzy method; stochastic number; deterioration norm