Abstract: Based on the laser raindrop spectrometer observation data from May to October 2019, the microphysical characteristics, raindrop spectrum distribution, particle falling velocity and Z-R relationship of precipitation particle spectrum in different precipitation cloud systems (stratiform cloud and convective cloud) in Longbao area of the Three-River Source Region were analyzed. The results show that: The microphysical characteristics of raindrops of convective cloud precipitation and stratiform cloud precipitation in the summer and autumn in the Longbao area of the Three-River Source Region were similar. The microphysical parameters of convective cloud precipitation raindrops were slightly larger than those of stratiform cloud precipitation. The raindrop spectrum of stratiform cloud precipitation and convective cloud precipitation showed unimodal distribution. Raindrop number concentration increased first and then decreased with the increase of precipitation particle diameter, the M-P distribution and Gamma distribution fit well for stratiform and convective cloud precipitation, The fitting of M-P distribution and Gamma distribution for stratiform cloud precipitation and convective cloud precipitation was good. Compared with the fitting of M-P distribution, the fitting of Gamma distribution could better reflect the bending characteristics of the fitting line of actual raindrop spectrum. The falling velocities of raindrops at different scales were different, and the range of particle velocities in convective cloud precipitation was slightly larger than that in stratiform cloud precipitation at the same scale. The traditional particle falling velocity fitting showed obvious underestimation, the high altitude and low air density were the main reasons for the observation speed greater than its falling velocity. The Z-R relationship of summer stratiform cloud precipitation was Z=418R^1.90 and the convective cloud precipitation was Z=630R^2.12, the traditional radar precipitation estimation method would lead to the underestimate of precipitation in this area.