Overflow device of fire truck

The utility model relates to an overflow device of a fire truck. The overflow device comprises an overflow hole formed in the top of a tank body, wherein an overflow pipe cap is sleeved on the top of the tank body, an opening of the overflow pipe cap is communicated with the inside of the tank body, the overflow pipe cap is used for sealing the overflow hole from the outer part of the tank body, an overflow pipe is arranged inside the overflow pipe cap, and the overflow pipe is used for communicating the inside of the overflow pipe cap with the outer part of the tank body. Through additionally arranging the overflow pipe cap, the situation that liquid in the tank body splashes and leaks outside due to slight shaking can be avoided, and impurities can be prevented from falling inside the tank body and influencing the operation of a water pump.