The invention discloses a longan orchard fertilization device which comprises a box body arranged on the top of a moving device, wherein a fertilizer storage chamber and a water storage chamber are formed inside the box body; the fertilizer storage chamber is positioned on one side of the water storage chamber; a mounting shell is fixedly arranged on one side of the box body; a limiting block is fixedly arranged on one side, which is far away from the mounting shell, of the box body; a driving motor is arranged on the inner side of the limiting block; a hydraulic cylinder fixed with the box body is arranged above the top of the limiting block; a piston rod of the hydraulic cylinder is fixedly connected with the driving motor; a rotating block is fixedly arranged on an output shaft of the driving motor. Due to matched use of the structures such as a water pump, a water outlet pipe, a hollow connecting block, a connecting pipe, a spherical nozzle and the like, fertilization can be performed by the fertilization device, surrounding longan trees can be watered and sprayed with liquid medicine to kill insects, the working efficiency is high, and the longan orchard fertilization device is simple in structure, low in manufacturing cost and flexible to use.