This paper mainly introduced Yichang-Wanzhou Railway Dazhiping Tunnel DK133+990 karst excrescent body's hydrogeology characteristics, karst development scale, water inrush and mud burst processes and characteristics of high-pressure water-rich cavern. According to karst cave project, hydrogeology condition and water inrush and mud burst mechanisms, cave processing should comprehensively take many factors, such as construction and operation safety, ect. into consideration, and abide by the principle of "releasing energy to reduce pressure, reinforcing by grouting, supporting in advance and processing comprehensively" .