Abstract: The analysis of degradation data is performed by building a degradation path model,which often has bad evaluation results for products whose degradation paths are unknown.However,the method presented isn’t based on the model of the degradation path.First,the reliability of products at each inspection time point is got using degradation information got from testing,and then a hypothesis on the distribution of life variables is made by using distribution families with guarantee parameters,last,the values of unknown parameters are got through distribution fitting,and a reliability assessment is performed.Furthermore,an example to compare with different methods is given,which demonstrates the feasibility and validity of this method.