As the core device of the next-generation all-optical communication network, optical switching chip has a serious impact on the capacity of optical switching node. In order to evaluate the degradation degree of the optical switching chip to the communication system, a simulation model of optical switching integrated chip with 32×32 Benes structure is constructed using the silicon-based electro-optical Mach-Zehnder interferometers. The relationship between the crosstalk of the optical switching chip and the crosstalk of the optical switch unit is analyzed, and the influence of the optical switching chip on the optical fiber communication system is studied. The simulation results show that the degradation of receiver sensitivity due to optical switch crosstalk can be expressed by the rational function with a linear denominator for a single polarization 200 Gb/s 64QAM signal. When the crosstalk of each optical switch element is less than -46 dB, the sensitivity degradation of the optical receiver is no more than 0.5 dB.