It is a major problem in the common calibration methods of automatic observation instrument for raindrop spectrum precipitation phenomenon in China at present that only the particle diameter and speed at a standard can be simulated; the diameter of the particle can be measured, but the velocity of the particle cannot be measured exactly; only smaller diameter particles and spherical precipitation particles can be simulated, but other shapes of precipitation particles cannot be simulated; the various types of precipitation particle diameter and speed cannot be covered, and so on. According to the needs of meteorological service, this paper elaborates a newtype integrated test system of raindrop spectrum precipitation phenomenon observation instrument from the design basis of simulated precipitation particles, the components of the integrated raindrop spectrum precipitation phenomenon observation instrument test system, the measurement methods and measurement accuracy of precipitation particle diameter and falling speed and so on. Through simulating particles with different diameters and velocities covering multiple types of precipitation, the measurement accuracy can be detected. This paper provides some standards and references for the domestic calibration and detection of raindrop spectrum precipitation automatic observation instrument in the future.