Based on wavelength division multiplexed (WDM) technology, quantum and classical signals can be transmitted together in the same fiber. However, the noise caused by the nonlinear interaction between classical signals and optical fiber will reduce the signal-to-noise ratio of quantum key distribution (QKD), so measures need to be taken to reduce the influence of classical noise. Different from the previous methods focusing on QKD device, the background noise rate, secret key rate and maximum secure transmission distance of WDM-QKD for different kinds of fibers are analyzed and compared by establishing the classical noises, decoy-state and finite-key models from the perspective of optical fiber transmission in this work. The numerical simulation results show that G.655 fiber can reduce the background noise rate of WDM-QKD, G.654 fiber can increase the secure key rate and the maximum secure transmission distance, while the performance of WDM-QKD with the popular standard single-mode fiber G.652 is in the middle of the three cases.