The invention discloses a quick calibration method based on pulse constant adjustment. The method comprises the steps that 1) the pulse constant of an ammeter is adjusted to original N times by adjusting a frequency division coefficient in a production process; 2) a resistor is connected in series with a connection SPI bus between a metering chip in the ammeter and an MCU in the ammeter to eliminate interference or jitter; 3) ammeter calibration is carried out through software to meet the requirement of a meter error; and 4) after production correction is completed, the frequency division coefficient is returned to a normal state, and the resistor which is connected in series with the SPI bus in the step 2) is removed, so that the pulse constant of the ammeter is returned to an original value. According to the invention, the pulse constant of the ammeter is adjusted to original N times by adjusting the frequency division coefficient in production; interference or jitter on the data signal transmission SPI bus is eliminated; after production correction is completed, the frequency division coefficient is returned to the normal state; the production efficiency is substantially improved; the production cost is reduced; and the method has a good application prospect.