With the application of mechatronics technology，electric measuring system of wheel load measuringinstrument is developed based on resistance strain measurement principle. The electric measuring system is tomposed of data acquisition circuit and upper computer wheel load measuring system software. Voltage signals fromstrain sensor pass through signal conditioning circuit，A/D conversion circuit and optical isolation circuit，on toMCU ultimately. Instructions and data transfer between MCU and PC wheel load measuring system via serial tommunication protocols. Users get wheel load value after data is restored and operated or result is restored at a specified directory as request. Weight as loading tool，the instrument is set above a tiltable jig and calibration by experiment. Errors are gained according to experiment data in which non-liner error is 1 0. 72%，repeated error is 11 .37%，hysteresis error is 1 1. 47% and comprehensive error is 12. 71%ultimately. It confirms that measurement accuracy and function performance of the instrument meet the pre designed requirements.