The characteristics of the largescale circulation background and mesoscale systems of the North China heavy rain storm occurred on 16 August 2005 are studied on the basis of the NCEP reanalysis data, surface hourly precipitation data, Doppler data and ShumanShapiro filter method. Results show that the heavy rainfall event occurred under the favorable environmental conditions, resulted fro m the interaction of midand lowlatitude systems. The mesoscale convergence and the mesoscale low triggered the occurrence of the heavy rainfall. Rain clusters bringing the heavy rainfall were related to mesoβ systems. The mesoβ mesoscale rain clusters appeared to the north of the cyclone center on 1000 hPa after filtering and to the south of the mesoα convergence line on 850 hPa.