The principle of circuit tolerance design, analysis and allocation are introduced, and a tolerance design method based on EDA simulation technology is presented. This method is a synthesis of several tolerance analysis including parameter sweep analysis, sensitivity analysis and worst case analysis, which could be used to simulate and confirm the key parameters which most effect the tolerance performance of the circuit. The method is applied to the PSK interface circuit using Saber. Follow the step, the nominal value of some electric components are adjusted, and the deviation of the value of the electric components are adjusted through tolerance allocation．The result demonstrates that the tolerance performance of the circuit has been improved. The research provides a new way to improve the reliability of aerospace electronic products.