Abstract: During rotor wind tunnel tests, the downwash flow generated by the model rotor produces significant wall interference due to the constraints imposed by the wind tunnel walls, with multiple parameters contributing to this interference. To investigate the impact of test parameters on the tunnel wall interference, an analysis method based on the Heyson approach was first established. Verification tests were conducted in both open and closed test sections of the FL-10 wind tunnel at the AVIC Aerodynamics Research Institute, confirming the effectiveness of the method. Subsequently, this method was utilized to analyze the parameter effects on tunnel wall interference. Finally, the Sobol algorithm was employed to calculate the sensitivity of wall interference to various test parameters. The results indicate that wall interference is minimized when the hub center is aligned with the wind tunnel center. The effects of wall interference on the rotor performance are opposite in open and closed wind tunnels, with more pronounced interference observed in the open tunnel. Among the investigated parameters, the advance ratio emerges as the most significant factor, exhibiting a sensitivity coefficient of 0.894. The thrust coefficient and the rotor model scale represent secondary influencing parameters, with total sensitivity coefficients of 0.144 and 0.155, respectively. These findings provide valuable insights into the mechanism of rotor-wall interference effects.