The invention discloses a rapid and convenient tree whitewashing device. The device comprises a supporting rod, a whitewashing board, a pull rod, a pressure water tank used for containing whitewashingliquid, wherein the rear side of the whitewashing board is a bendable stainless steel sheet, the front side of the whitewashing board is soft cloth, the periphery of the soft cloth is connected withthe periphery of the stainless steel sheet, a spray pipe is arranged inside the whitewashing board, the spray pipe is connected with the pressure water tank, the end part of the supporting rod is connected with one side of the whitewashing board, a connecting rod is arranged on the other side of the whitewashing board, a hanging buckle is arranged on the connecting rod, and the pull rod is matchedwith the hanging buckle. According to the device, the soft cloth can adsorb the whitewashing liquid sprayed out by the spray pipe, so that the uniformity of whitewashing is guaranteed, meanwhile, liquid waste can be avoided, due to the fact that the length of the supporting rod and the length of the connecting rod are long, clothes can be prevented from being sprayed, the trouble of cleaning is avoided, and the whitewashing efficiency is improved.