The distribution of the surface elements of two rainstorm processes is analyzed during 6-7 and 9-10, July 2005 by using the surface automatic meteorological station data and satellite data. It shows that the strong rainfall belt lies near the nonfrontal baroclinic zone and baroclinic troughs. Using the NECP data, the dynamic mechanis of the nonfrontal baroclinic zone and baroclinic troughs causing strong precipitation are revealed by the thermal wind helicity of the second kind and the ageostrophic wet Qvector, it indicates that frontogenesis and baroclinic zone easily occur in the surface nonfrontal baroclinic zone and baroclinic troughs, and then they may induce the strong precipitation.