By using weather radar, upper-level and ground observations and NCEP 1°×1° reanalysis data, this paper analyzes the characteristics of mixed-type convective weather during the formation and development of Jianghuai cyclone in spring, and the reasons why different types of convective weather occur and intensify. The results show that there are differences in spatio-temporal distribution and convective characteristics of different types of severe convective weather. The localized hail is mainly produced by discrete convective line in the formation stage of cyclone, the banded short-time severe precipitation is produced by TL/AS MCS which is located on herringbone convective line in the formation stage of cyclone and behind the S-shaped convective line in the development stage of cyclone, and the large-scale gale is produced by TS MCS on the S-shaped convective line in the development stage of Jianghuai cyclone. Jianghuai cyclone is the result of the baroclinic development of the large-scale weather systems, convective activities enhance the convergence of the low-level〖JP2〗 front, strengthening the formation and development of cyclone. The generation of severe convective weather is closely related to the dynamic and thermodynamic field of Jianghuai cyclone. In the cyclone formation stage, the southwest vortex combined with the mountainous terrain provides the environmental field conducive to the formation of hail in the southwest of Hubei Province. The warm shear line in the cyclone formation stage and the cold shear line affected by the south branch trough in the cyclone development stage provide the environmental field conducive to the formation of storm train effect which produces 〖JP2〗short-time severe precipitation. In the cyclone development stage, the cold shear line provides the environmental field conducive to the formation of the rear inflow jet, which is the main factor of gale formation.