Abstract: Based on the partition of sample space which is constituted by symbol decision events, the approximate Bit Error Rate(BER) formula with the miss matched amplitude of the successive interference canceler (SIC) is generated from the formula of total probability and independence of the symbol decision event.The effect of the miss matched amplitude on the BER performance is discussed by the application of the approximate BER formula and the character of the error residuals incurred by the miss matched amplitude.The result shows that the BER performance of SIC would be enhanced with the decrease of the miss matched amplitude rate.Simulation results agree well with those of theoretical prediction and the increase of BER is not distinct when the miss matched amplitude rate is less than 20％.

Key words: successive interference canceler, approximate analysis, miss matched amplitude