Based on the cloud physical probe data of 11 aircrafts carried out in Guangxi in November and December 2012, the macro and micro physical structure characteristics of stratiform clouds are studied and the precipitation mechanism of stratiform clouds is discussed. The main results show that the microphysical characteristics of stratiform clouds in Guangxi are significantly different from those in other parts of China. The typical vertical microphysical structure of stratiform clouds is: droplets are generated by condensation in the lower layer and develop with the updraft; the number concentration and average diameters of cloud droplets and liquid water content gradually increased with height; the droplet spectrum broadened, and the spectral pattern extended to large scale; they increased to a maximum value at the upper level of the clouds and decreased with height subsequently. The ice particles in the layer of altostratus with a cloud structure of cool and warm mixed affected the microphysical structure after falling into the warm layer, mainly broadening the droplet spectrum and increasing the CIP vertical distribution amplitude of droplet diameters, which was conducive to the initiation and development of the collisioncoalescence process in the warm layer. The microphysical horizontal distribution of the stratocumulus showed discontinuous jump variation and there was the convection bubble structure. The microphysical quantities within the convection bubble were higher than those outside the bubble; cloud droplet spectral pattern varied toward large scale; the convection bubble structure was the important mechanism for the formation of stratocumulus precipitation.