Abstract: Based on conventional observation data, the surface observation of automatic weather station, wind profile data from Doppler radar,satellite images and NCEP 1°×1° reanalysis data, the contrast analysis for two successive torrential rain processes occurred in Shandong province on 8 July and 10 July 2012 is made. The results indicate that the former process occurs against the circulation background of the subtropical high pressure continuously strengthened and unstable energy increased, and the later process takes place against the circulation background of the subtropical high pressure weakened and withdraw towards south as well as unstable energy released. The common large scale environmental conditions of the two processes include that the vertical motion and the low-level jet developed intensely over the torrential rain area and it has divergence at the upper-level, convergence at the middle and lower level. There are differences between the two processes.In the former process, intensity and distribution of severe precipitation is consistent with strong vertical upward movement, strong convergence in the low-level, strong divergence in the upper-level and water vapor flux convergence center. But in the latter process, the consistence mentioned above is poorer than that in the former one. Strong development of southwest jet is corresponding to the periods of severe precipitation in the two processes. Development height of southwest jet is lower, the wind is much stronger, and when severe precipitation ended the downward dissemination speed of cold air is faster and the height of cold air is lower in the latter process than that in the former one. It has a certain prediction significance for severe precipitation nowcast that with lower cloud top temperature, higher development level of convection system, longer continuance of cloud top temperature center below -70 ℃, severe precipitation emergences in the low value center and in the great gradient zone of cloud top temperature in the latter process.