Abstract: The tendency factor was introduced into the voting model in Vague sets,and the weighting method for the influential factors of reliability was proposed.Combined with the fuzzy decision-making theory,the model synthetically assessing the relative failure coefficients between the units of a system was developed.The approach to fuzzy reliability allocation for an aeroengine digital control system with cold standby units was presented with the aid of the model and MATLAB.This approach is suitable for conceptual and preliminary design where there is lack of system reliability data.