The invention discloses an automatic cleaning device of a rotary screen for producing compound fertilizer. The device comprises a transmission device and a vibration device; in the transmission device, a driving sprocket fixed on a main shaft of the rotary screen is connected with a driven sprocket arranged on a vibration main shaft through a transmission chain; and in the vibration device, the vibration main shaft is arranged on a shell of the rotary screen through a bearing device, a cam is arranged on the vibration main shaft, the cam corresponds to a fixed ring, a guide cylinder is fixed right above the topmost point of the fixed ring through a rib plate welded with the shell of the rotary screen, a vibration ball is connected with a lever through soft connection and placed in the guide cylinder, and the level is connected with a guide pivot welded on the shell of the rotary screen. The passing rate of cleaning the screen by using the device can reach over 90 percent.