To further study the characteristics of aerodynamic pressure acting on the tunnel wall，the entire process of a high-speed train passing through the double-track tunnel was simulated based on the RNG k-ε two-equation turbulence model and the sliding mesh technique.Then，the accuracy of numerical method was verified by comparing the results between numerical simulation and field measurement.Finally，the influences of the train-to-tunnel area ratio on the characteristics of aerodynamic pressure acting on the tunnel wall were analyzed in detail.The results show that：the maximum gradient and positive peak values of the initial pressure wave both increase exponentially with the increase of train-to-tunnel area ratio，and the correlation coefficient R2 is greater than 0.998；at two stages of before or after the train tail leaving the tunnel exit，the relationship between the typical peak values of aerodynamic pressure（positive peak，negative peak，and peak-to-peak）acting on the tunnel wall and the train-to-tunnel area ratio is the exponential function with the ε as the base，and the correlation coefficient R2 is greater than 0.9995.After the train tail leaving the tunnel exit，the difference between the positive and negative peak values of the aerodynamic pressure acting on the tunnel wall at different train-to-tunnel area ratio decreases with time.Taking the measurement point there 500m away from the tunnel entrance as an example，when the train-to-tunnel area ratio increases from 0.0801 to 0.1122（1.4 times），the increments of the maximum gradient and positive peak values of the initial pressure wave are 2.92 and 0.30kPa，respectively；the increments of the positive and negative peak values of the aerodynamic pressure before train tail leaving the tunnel exit are 0.35 and 0.60kPa，respectively；the increments of the positive and negative peak values of the aerodynamic pressure after train tail leaving the tunnel exit are 0.53 and 0.46kPa，respectively.