The influence of the high order sideband suppression ratio on the all-optical wavelength conversion system of the polarization multiplexing signal of parallel pumps based on carrier suppression is theoretically analyzed and simulated. According to the character of Bessel function curve, the optical sideband power with different frequencies is changed by controlling the radio frequency signal voltage and adjusting the modulation depth of the Mach-Zehnder modulator, then the parallel pump light with the same polarization direction, locked phase and different high order sidebands suppression ratios are obtained. The receiving bit error rate performance of the converting light under different sidebands suppression ratios is analyzed. The theoretical analysis and simulation results show that the bit error rate of the converted light on the x and y polarization directions can achieve 10-10 by controlling the modulation depth of the modulator in the range of (1.7,2.0), and the parallel pump light with the sidebands suppression ratio in the range of (7 dB,18 dB) is got correspondingly. The signal can be received by direct-detection without crosstalk. So there is no need to filter out the vestigial sidebands by using filter. It not only reduces the complexity of the system but also saves the system cost.