In order to make quantitative analysis on complex electronic system，a novel non- probabilistic reliability analysis method based on evidence theory is proposed. The plausibility function and belief function are the upper and lower bounds respectively，then the uncertainty propagation is implemented through the system model. Comparing with conventional reliability analysis method based on stochastic model，the proposed method needs neither prior nor conditional probability，thus it can be applied to small sample condition. Good performance of the proposed method is demonstrated by simulation results.