Torque calibration method and system for transmission shaft of vehicle

The invention discloses a torque calibration method and system for a transmission shaft of a vehicle; the method comprises the steps: determining a calibration rotating speed of the vehicle, and calculating a calibration vehicle speed according to the calibration rotating speed; controlling the vehicle to accelerate to a calibrated vehicle speed at a preset gear, and then controlling the chassis dynamometer to run under the driving wheels at a preset speed; according to different gears and different accelerator pedal opening degrees, regulating the accelerator pedal tto the preset opening degree and lasts for preset time, and meanwhile recording the first driving force output by a chassis dynamometer and torque voltage output by a torque sensor of a transmission shaft of a driving wheel; calculating the driving torque according to the first driving force obtained by each accelerator pedal opening degree under each gear and the tire rolling radius of the driving wheel, serving as the first driving torque corre