The amplifier model with XPM effect is given. The XPM has an effec on the small-signal gain. The deviation caused by XPM effect in EDFA is stronger with the increasing of nonlinear coefficient, pump power and amplifier length. Simulation results prove: to neglect the XPM originating in the EDFA is inaccurate. This is particularly true when its higher coefficient of nonlinearity is taken into account, even in r >0.01/W.m, XPM in the first EDFA of a cascade EDFA can't be negnected.