Overflow-preventing gas-blocking floor drain

The utility model discloses an overflow-preventing gas-blocking floor drain which comprises a face cover, a cylinder vertically fixed with the face cover, a gas-blocking cover and a guide rod. An anti-blocking screen is arranged on the face cover, a bend more than 90 degrees is arranged at the lower end of the cylinder, a gas-blocking water storage area is formed on the inner side at the bottom of the cylinder, the gas-blocking cover comprises a gas-blocking cylinder and a cover lid arranged at the top of the gas-blocking cylinder, the lower end of the gas-blocking cylinder of the gas-blocking cover falls into the gas-blocking water storage area, a positioning rod is arranged on the lower end face of the cover lid of the gas-blocking cover, the end of the positioning rod is butted against the end face of the lower end bend of the cylinder, the guide rod is fixed in the middle of the upper end face of the cover lid of the gas-blocking cover, a guide hole is arranged at the center of the anti-blocking screen, t