In the short-distance， multi-user quantum key distribution integrated optical fiber network scene， aiming at the problem that when the quantum channel and the classical channel are close to each other， the four-wave mixing noise generated by the classical light is easy to have a serious impact on the performance of quantum key distribution， a theoretical model is constructed to describe the deterioration of the performance of discrete variable quantum key distribution caused by the four-wave mixing effect. In order to suppress the influence of four wave mixing noise， four noise suppression schemes were built and analyzed in OptiSystem and MATLAB， which realized the simultaneous co-channel transmission of seven 10 Gbps classical signals and one quantum signal. The minimum bit error rate of classical signal is 8.13×10^-11， and the quantum bit error rate is up to 1.69% at the minimum. The research results are of great significance for promoting the practical process of quantum-classical co-channel transmission system.