Abstract: The jamming effect of the suppressing noise frequency modulation(NFM) jamming on the pseudo-random code phase modulation and sine FM（PRCPM-SFM）combined pulse train fuze was investigated. Firstly, an analysis model of the jamming effect for the combined fuze was set up. Secondly, the overall signal to jamming ratio (SJR) gain of the correlator output signal was reduced under the NFM jamming. Thirdly, the valuation method of the suppressing NFM jamming effect was derived in terms of the overall SJR gain. Finally, the factors influencing the jamming effect were discussed. The result shows that the jamming effect of PRCPM-SFM combined pulse train fuze under the suppressing NFM jamming can be improved effectively by utilizing these factors reasonably