Abstract: During the tunnel excavation,forecast technique for advance geology is an effective means to avoid geological disasters induced by unfavorable geologic bodies. Relying on Dingzhai flood control and drainage tunnel project,the method of combining the seismic elastic wave method and the seismic reflection method was used to detect the unfavorable geologic bodies and the water-rich condition of the rock body aiming at complex geological conditions such as weak interlayers or karst development and rich water in the rock mass in the tunnel construction area. In the receiving hole,the waveform corresponding to each excitation hole was collected. For the areas where the shear wave negative reflection interface exists,the areas where positive and negative reflections alternately appear,and the areas where dense tomographic response appears in the migration image,it is predicted that the joints and fissures here are very developed or there are weak interlayers. According to the seismic signal inversion result,the water-rich areas of the rock mass are predicted,and corresponding engineering measures are proposed. It ensures the safe and efficient excavation of the Dingzhai flood control and drainage tunnel,and also provides a reference for the construction of similar projects.