Abstract: A single step-stress acceleration life test method for hybrid thick film DC-DC converters was proposed.Sampling three kinds of hybrid thick film DC-DC converter,the acceleration life tests were conducted by raising the environmental temperature and under fixed-time curtailment,which can finish the sample′s reliability assessment in a relatively short time.By analyzing the failed sample,it was able to determine the fault of design & process,provide basis of improvement,and lay the foundation of passing reliability qualification and realizing space use for the hybrid thick film DC-DC converter.