Abstract: This paper focuses on the statistical analysis for step-down-stress accelerated life testing. A new 3-step analysis method was brought forward, the key procedure of this method was fully explained under Weibull distribution, and the solution of the estimation question in data conversion as well as the algorithm concerned was presented. A numerical example was given to illustrate the method in the end. 3-step analysis method doesn’t rely on accelerated model, and simplifies the complexity of the analysis procedure. It has a high statistical analysis precision and a good constringency, and it is beneficial to the engineering application of life evaluation and life extension in weapon equipment.

Key words: systematic evaluation and feasible analysis , accelerated life testing , step-down-stress ALT , 3-step analysis method , reliability