The invention discloses a waterproof anti-explosion box for a cable middle connector. The waterproof anti-explosion box comprises an upper cavity and a lower cavity connected through bolts, the upper cavity and the lower cavity are covered to form a middle connector bin, fast sand filling ports are formed in the upper portion of the upper cavity, end heads are arranged at the two ends of the upper cavity and at the two ends of the lower cavity, a plurality of waterproof grooves are formed in the inner walls of the end heads, and seal rings are arranged on the waterproof grooves. Cover bodies are arranged on the fast sand filling ports, and sealing flat gaskets are arranged between the cover bodies and the fast sand filing ports. The waterproof grooves and the seal rings are arranged on the upper cavity and the lower cavity, the waterproof effect is good, the fast sand filling ports are formed in the upper portion of the upper cavity, and the upper cavity can be conveniently filled with waterproof anti-explosion sand. The waterproof anti-explosion box for the cable middle connector is simple in structure, and can effectively prevent water from entering the anti-explosion box in the state of 1M water depth and provide the good operation environment for the middle connector. By means of the waterproof anti-explosion box for the cable middle connector, the waterproof performance of the cable middle connector is improved, cable faults caused after the middle connector is soaked in water are avoided, and the stable operation of a power grid is maintained.