Method and system for gear calibration of gearbox

The invention provides a method and system for gear calibration of a gearbox. The method comprises the steps that S1, vehicle clutch signals are collected in real time, and when the collected vehicleclutch signals develop from nothing and the time of duration exceeds a time threshold value, it is considered that the clutch signals are valid; S2, after clutch loosening, the engine rotating speed and the gearbox output shaft rotating speed of a vehicle running at the current gear are collected at set intervals; S3, the ratio of the engine rotating speed and the gearbox output shaft rotating speed is calculated so as to be used as the current gearbox gear speed ratio of the vehicle; S4, a corresponding gear value is obtained in a matched manner according to the current gearbox gear speed ratio of the vehicle; and S5, if within a period of time, the probability of a certain gear value is larger than a probability threshold value, the gear value is calibrated as the current actual gear ofthe vehicle. The system co