Based on the PMS data obtained during a returning process, the inhomogeneity of stratiform clouds in returning processes was analyzed from the aspect of microphysical structure. It is found that when the aircraft flies into stronger precipitating cloud bands, the main cloud physical parameters (liquid water content, particle mean diameter and concentration, and temperature) change greatly; the liquid water content, the mean diameter and the particle concentration leap up; spectrum width becomes wider; temperature drops; and so on. In the stronger cloud band, temperature variation is smaller and meanwhile temperature is lower. The stronger precipitating cloud bands have abundant ice crystals, indicating better natural seeding potential.