After diagnosing the operational meteorological data, the satellite cloud pictures, and the intensive surface observational data, it was found that there were six surface mesoscale rain clusters (1 hr rainfall≥10mm, life cycle≥3hr) formed in succession in the two meso-a cloud clusters causing the torrential rain in Hebei in August 1996. And, associated with the clusters, there were several surface mesoscale systems closely related to the surface moist baroclinic front and the surface convergency in their development.