Tunnel conditions are the main scene of subway operation. The increase in operating speed and the increase in wheel roughness lead to increased noise and reduced passenger comfort. Based on the actual measurement results of a certain line, the quantitative relationship between the noise in the car and the roughness of the wheels under tunnel conditions is studied. When the train runs in the tunnel at a speed of 60 km/h, when the wheel roughness is A-level roughness, the noise in the car is 76.5 dBA, when the overall roughness amplitude of the wheel exceeds the A-level amplitude by about 11 dB, the noise inside the vehicle reaches 83.3 dBA; when the train runs in the tunnel at a speed of 80 km/h, when the wheel The interior noise is 80.3 dBA. When the overall roughness amplitude of the wheel exceeds the A-level amplitude by about 6 dB, the interior noise reaches 83.1 dBA. At this time, the total value of the interior noise exceeds the relevant standard limit; When running in a tunnel, when the wheel roughness is grade A, the noise inside the car is 82.9 dBA, and the total value of the noise inside the car has reached the relevant standard limit. According to the analysis results, the wheel roughness control suggestions are put forward.