Abstract: To facilitate the calibration process of electronic-controlled injector, a study on the calibration of fuel quantity and buildup of basic MAP was made. Chief factors affecting fuel injection consistency and identity were analyzed. A method for fuel injection consistency and identity improvement was designed by controlling the common rail pressure fluctuation and modifying the fuel injection pulse. The initial fuel injection MAP was achieved by the method of variable step interpolation, then the accuracy of the basic fuel injection MAP was tested. A test on an engine equipped with the calibrated common rail electric control injection system was carried out. The experimental results proved the rationality of the initial fuel injection MAP.