The invention discloses an automatic spraying device for automobile bumpers. The automatic spraying device comprises a security moving base, the bumpers and a nozzle. A support column is arranged on the top of the security moving base. The bumpers are arranged on the top of the support column in a penetrating manner. The nozzle is arranged on one sides of the bumpers. An ultrasonic transmitting and recovery device is arranged on the top of the nozzle. A rotary arm is arranged at one end of the nozzle. The nozzle is movably connected with the rotary arm. A first rocker arm is arranged at one end of the rotary arm. The first rocker arm is movably connected with the rotary arm. A second rocker arm is arranged at one end of the first rocker arm. The second rocker arm is movably connected with the first rocker arm. A controller is arranged on the outer wall of the second rocker arm. A controller body is arranged in the controller. A fixing seat is arranged at the bottom of the second rocker arm. The fixing seat is fixedly connected with the second rocker arm. By the adoption of the automatic spraying device for the automobile bumpers, the waste of a great amount of spraying fluid can be avoided, the large area of the spraying fluid is absorbed through a spraying fluid adsorption nozzle, and the influence on the body health of people can be avoided.