A measurement circuit and a measurement method for measuring and updating a voltage resolution of an electronic atomizer circuit are provided. In the measurement circuit, a comparison unit is configured to compare a first preset value and a second preset value to obtain a voltage difference, an accumulation and subtraction unit is configured to perform counting according to a comparison result, and a control unit is configured to adjust the voltage difference between two compared voltage input terminals, thereby calculating a voltage resolution of the control unit, avoiding the impact of the actual error of the first constant current source and the unit resistor on the actual voltage resolution, and ensuring the measurement accuracy. In addition, an accurate to-be-measured voltage is calculated, and a measurement value of the to-be-measured voltage is corrected, to ensure the high measurement accuracy of the to-be-measured voltage and the output power.