Abstract: Using the tolerance analysis software CE/TOL, the tolerance analysis model is established by taking the distance between the sub-boards of the frequency hopping processor as the closed loop. Through the analysis of sensitivity and contribution, the key dimensions that affect the tolerance of the closed loop in empirical design are determined and removed from the assembly dimension chain by improving the structural configuration; Through measurement variation analysis, the tolerance of the composition loop after improvement is optimized，the connector insertion success rate is increased to 99.73% according to the principle of limit value of random error. CE/TOL can quantitatively analyze the influence of the installation mode of parts and the change of dimension tolerance on the connector insertion success rate of the product, which provides a reference design idea for the plug-in reliability design of complex assembled electronic products.