The basic principle of accelerated degradation test and several widely-used accelerating models were described firstly in this paper. Then temperature and humidity were selected as accelerating stress by analyzing main factors impacting the reliability of smart meters online. The maximum of accelerating stress was determined via diagnostic test, and the optimized accelerating stress combinations were given. After determining the failure thresholds of the degradation characteristic quantity, sample size and their proportions, and measurement times, the test procedures were given at last. This scheme was of high practicability.