A preliminary study was conducted about the cause of split for its centre of the tropical storm 9216 at 02Z Sep. 1. A new centre was formed because of the strength of cyclonic circulation in the tropical storm trough area due to the southeasterly jet at the lower layer and the attraction and merging of a vortex. The conditions of heavy rain at Qingdao City are of abundant moisture,severe ascending air,and of the influence of the eastward motion of a longwave trough.