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Utilizing the TRMM precipitation and cloud feature database, the seasonal differences of vertical structure, areamean rainfall rate and spatialtemporal distribution of precipitation for convective systems with different echo top heights over the South China Sea between January 2001 and March 2012 are analyzed. The results show that the reflectivity greater than 20 dBz of shallow, relatively deep and deep convections was respectively concentrated in 4-8 km, 4-10 km, 4-14 km, respectively. The frequency of 20 dBz echo top height peaked at 9 km for shallow convections. In winter, the frequency of 20 dBz echo top height peaked at 13.5 km and 14 km respectively for relatively deep and deep convections. However, in other seasons, their peaks were further higher arriving 14.5 km and 16 km. Relatively deep and deep convections were both two main precipitation systems with large rainfall rates in the South China Sea. Relatively deep convections have stronger rainfall rates in summer and autumn, while deep convections have stronger rainfall rates in winter and spring. Winter has the least number of relatively deep convections and deep convections, while spring has the least number of shallow convections. Shallow convections tend to occur in the south of 12°N and deep convections tends to appear in the north of 12°N. Relatively deep convections develop in the south of 12°N in winter and spring, but across the South China Sea in summer and autumn. For relatively deep convection events, there is a deviationcenter of cyclonic convergence in the northern South China Sea. The southwest water vapor transport difference in the central and southern South China Sea and the different convergence of water vapor below 700 hPa are the main reasons for stronger precipitation rate in summer and autumn than in winter and spring.