Abstract: After the occurrence of "2021.7.20" rainstorm in Zhengzhou, the description of rainstorm characteristic information becomes the focus of the network, and all kinds of views that cause public misunderstandings fill the network. This paper collects the chaotic information spreaded on the Internet from three aspects:the spatial scale, the temporal scale and the recurrence period of extreme rainstorm, discusses the causes of the chaos from the aspects of the standardization of temporal and spatial elements of rainstorm characteristics, the sharing degree of rainstorm original monitoring data and characteristic information, and the science of rainstorm recurrence period. The main conclusions include:Information distribution should be timely, standardized and accurate, which is the best way to deal with the dissemination of false information. Some departments, such as water resources, meteorology and emergency management, should correctly analyze the problems existing in the dissemination of rainstorm characteristic information, consolidate the work foundation, optimize the cooperation mechanism and publish authoritative information in time.