本文对准直光束射入含有非线性介质的Ｆ－Ｐ干涉仪内的光场分布进行了研究．由于非线性介质与光的作用，从Ｆ－Ｐ干涉仪出射的光束截面上的相移随位置的改变呈一定的分布，进而引起了干涉仪的透射率和输出光束重新分布。当干涉仪两个面的反射系数较大时，输出光束截面出现光强和相移的跃变．这种现象与以前在平面波假设下所得的光强分布所得结论有较大的不同． In this paper, the distribution of collimated light beam into the F-P interferometer with nonlinear medium is studied. Due to the nonlinear medium and the action of light, the phase shift in the beam cross section emerging from the F-P interferometer varies with the position, resulting in the transmission of the interferometer and the redistribution of the output beam. When the reflection coefficient of the two surfaces of the interferometer is larger, the intensity and phase shift of the output beam cross section appears. This phenomenon is quite different from the previous conclusion on the distribution of light intensity under the assumption of plane wave.