Anti-reflux underground overflowing and discharging device

The utility model provides an underground overflowing and discharging device capable of preventing backflow. The cylinder comprises a cylinder body, an upper joint and a lower joint, wherein the upperjoint is connected and fixed at one end of the cylinder body; a guide head is arranged in the upper connector, and the end, close to the cylinder body, of the guide head is fixedly sleeved with a supporting rod; the end, close to the cylinder body, of the upper connector is fixedly connected with a pawl spring, and a steel ball is placed in the pawl spring and abuts against the end, away from theguide head, of the supporting rod. A shearing piece is arranged between the pawl spring and the supporting rod, the outer side of the lower connector is in threaded connection with a sealing body, the sealing body is fixedly connected to the end, away from the upper connector, of the cylinder body, a ball seat is arranged in the sealing body, a soluble ball is fixedly installed at the end, away from the steel ball, of the