Abstract: In this paper, based on the repair as new model, under the same storage condition, the spare parts number M for N identical systems is derived on the condition that failures are repaired with probability P_0. For system which follows Weibull distribution, utilizing the pivotal quantity and Fiducial distribution, the upper confidence limit of the spare parts number M is defined; futhermore, based on the complete samples in life testing, utilizing the Fiducial method, the computation of the upper confidence limit of the spare parts number M is given in the end.