Tunnel cable trench anti-backflow drainage device and drainage system

The utility model utility provides a tunnel cable trench anti-backflow drainage device and a drainage system. The device comprises a water inlet pipe, a water conveying belt and a floating block, the water conveying belt is used for communicating a cable trench and a drainage ditch, one end of the water conveying belt is communicated with the water inlet pipe, the other end of the water conveying belt is connected with the floating block, and the floating block is used for driving one end of the water conveying belt to float on the water surface and keeping an opening of the end, located in the drainage ditch, of the water conveying belt above the water surface; the flexible water conveying belt and the floating drainage mechanism are arranged to form a one-way drainage channel, water in the drainage ditch is prevented from flowing back into the cable trench through the water conveying belt under the sealing effect of the flexible water conveying belt when no medium exists, the floating drainage structure mai