Dual permanent magnet synchronous motors (PMSMs) based electric powertrain has been widely used in electric vehicles. Torque ripple caused by current measurement errors has a huge impact on the performance of dual-PMSM based electric powertrain. Currently, the measurement errors of current sensors in a dual-PMSM system are individually calibrated results in inconsistent calibration standards. The inconsistent calibration for errors of current sensor affects the current distribution of dual-PMSM based electric powertrain, thus making the motors unable to output power based on the specified ratio. To unify the calibration standards of dual-PMSM subsystems, a fast calibration method with high reliability is proposed in this article. The proposed calibration method is able to: check the rationality of the compensation values to eliminate the wrong value in the sampling process, and calibrate within one second even under the conditions of load distribution, speed mutation, no-load, interference or noise. A 2 kW dual-PMSM based electric powertrain testing rig is employed to verify the effectiveness of proposed calibration method.