The wave rotor refrigerator (WRR) is an efficient refrigeration technology. For the purpose of investigating the gas wave characteristics inside the rotor channels of WRR device, the performance and pressure monitoring experiments were conducted at various pressure ratios in this study, and the main findings are as follows: the computation method can produce an accurate design of pressure ports though the post-wave gas pressure of numerical computation has a certain difference with the experiment because of the actual gap leakage and friction loss. The deviation of working pressure ratio from the design values results in the reversed/reflected compression waves or worsens gas leakage, which lowers the equipment performance. When the expansion ratio α is constant, the efficiency reduction ratio does not exceed 11.9% as the relative variation rate of the compression ratio is less than 150%; When the compression ratio β is constant, the efficiency is relatively lowered by a proportion less than 16.4% as the relative increasing ratio of α is less than 63%. This study improves the mechanism of WRR and demonstrates the strong ability of WRR to resist fluctuations in working conditions.