Abstract: In order to obtain the impact of cross-phase modulation(XPM) on the microwave photonic switching with nonlinear optical loop mirror(NOLM) the numeric analysis platform with XPM is established by the split-step Fourier method that can solve the coupled nonlinear SchrÖdinger equation,and the impact of XPM on the carrier signal modulated by the microwave and the power transmission function of NOLM Tm is obtained.The simulation results showed that XPM induced the distortion of waveforms and the leak of side lobes.And the larger the modulation bandwidth was,the larger the leak of side lobes.Furthermore,Tm was distorted because of the XPM-induced nonreciprocity:Tm decreased when the splitting ratio of the coupler f∈(0,0.5) and increased when f∈(0.5,1).