Abstract: To further study the hydrogeological characteristics and electrical response regularity of red bed areas in Southern Jiangxi, the typical areas are selected for comprehensive geophysical prospecting. By analyzing the hydrogeological characteristics of fissure water in the Cretaceous clastic rocks, it is found that the groundwater types in the area are mainly Cretaceous pore water and fissure water. The aquifer contains mudstone interlayer and the water abundance of pore water is relatively poor. Moreover, the structures are mainly faults and fissures, and the fissure water is relatively rich in water. The audio frequency electric method, audio magnetotelluric method and IP method are used for a comparative study of the fissure water in Cretaceous clastic rocks, the results show that when intact Cretaceous clastic rocks have relatively high resistivity, low polarizability and half-decay time, the resistivity of strata where faults and fissures are developed is low. While the polarizability and half-decay time are large, the curve shape is obviously abnormal. The study of electrical response characteristics can improve the success rate of water exploration and provide important references for solving the problem of water shortage in Southern Jiangxi.