Abstract:A large-scale convective gale event was studied based on conventional observation data, automatic weather station data, GFS analysis data at spatial resolution of 0.25°and temporal of 6h, observations of Doppler radar , and Fengyun-4 satellite data in East China on 12 April 2020 under the background of consistent northwesterly air flow from the lower to the middle layer behind the North China Cold Vortex. The results demonstrate that after the strong cold air gales moved southward on the morning of the 12th, a convective storm was triggered near the drylines at the junction of Shandong and Jiangsu province on the afternoon in the favorable thermal background of cold advection at the middle level and warm advection at the lower level, the convective storm occurred in the area with a large temperature difference between 500hPa and 850hPa and the initial shape of the convective cloud matches the dryline well;The convective system was strengthened under favorable conditions such as better water vapor condition, stronger wind speed in the middle layer, merged of gust front and the influence of the special land and sea distribution in Hangzhou Bay, which caused the large-scale convective gale weather in Jiangsu, southeast Anhui and north Zhejiang again, and 13 extreme gales occured near the Zhoushan Islands ; The 13 extreme gales occurred at the fracture area of echo and theγ scale mesoscale vortices, which caused by the radiation of rear inflow jet and the strong downdraft, smooth underlying surface, fast-moving convection system and small-scale downburst currents within the system.