Since a certain type of missile electrical connector is a product with high reliability and long lifetimeit is difficult to obtain failuretotime data in a short time.For assessing the reliability of the producta stepstress accelerated degradation test was designed based on analysis to its failure mechanism.Thenthe reliability function at the normal use stress level was extrapolated from the accelerated degradation data.In the testthe contact resistor was taken as the performance index and temperature was used as accelerated stress.When analyzing degradation dataWiener process was adopted to model the degradation process.A maximum likelihood function integrating all the degradation data was established for improving the accuracy of estimation.The results show that the proposed approach based on analyzing accelerated degradation data is practical and effectivewhich can realize the reliability assessment of the missile electrical connector and can be extended to evaluate the reliability of other highly reliable products.