Abstract: A measurement system based on the electric resistance micro-force sensor was designed to measure droplet mass deposit promptly without using tracer. The calibration test results showed that there was a good linear relation between the droplet mass deposit and the output voltage of sensor, and the determination coefficient was 0.999, therefore, the calculation model was built to provide measurement basis for the system. To improve measurement resolution, the high-precision micro force sensor was selected, the micro force was amplified by using the lever and the friction resistance was reduced; the measurement resolution reached 0.003 3 mg/cm~2. The results of comparison test between the system and the tracer method showed that the relative errors were 5.13% and 6.13% for measurements on the horizontal and vertical planes respectively, indicating that the system had good precision. Tests to research the influences of the temperature, the air velocities, the liquid evaporation and the pesticides species on measurement precision were conducted, and the results showed that the influences on the measurement precision by these factors were small and the system had good stability. The measurement system provided a method to measure droplet mass deposit promptly for spraying regulation research and had good practicability.