Using radiosonde and FY 2E Satellite data, a quantitative analysis of satellite cloud images and physical fields is conducted on two rainstorm processes induced by the subtropical high and westerly trough in August 2005 and August 2010. It is found that there was a continuous complete cloud band at the east of the trough line at 500 hPa and near the boundary of the cold air side, the cloud band was smooth and neat. The cloud system was a typical frontal cloud system, and from a structural point of view, the frontal cloud band was mainly composed by the multi layer cloud systems. The entire cloud band was located between line 580 and line 588, which was composed of convective clouds, a stable precipitation cloud band and mixed precipitation cloud band. The convective clouds were concentrated near the clear zone at the edge of the subtropical high, usually located close to the subtropical high between line 584 and line 588. The stable precipitation was concentrated on the back of the cloud band between line 580 and line 584; the mixed precipitation occurred in the vicinity of the line 584 between two cloud systems. The distribution of the cloud system had a very good correspondence with the vertical velocity field, vorticity field, divergence field, and high level vorticity advection field. The distribution characteristics of temperature and humidity parameters, such as humidity flux, humidity flux divergence, and pseudo equivalent potential temperature, gave a clear explanation of the movement, development, and distribution characteristics of the frontal cloud bands.