The invention discloses a fertilization device for mushroom cultivation and an operation method thereof. The device comprises a bottom frame, a box body is fixedly connected to the left side of the top of the bottom frame, a supporting frame is fixedly connected to the position, located at the left side of the box body, of the left side of the top of the bottom frame, and a fixing frame is fixedlyconnected to the top of the supporting frame; and the left side of the top of the fixing frame is fixedly connected with a connecting plate. Through cooperative use of the bottom frame, the box body,the supporting frame, the fixing frame, the connecting plate, a top plate, a first motor, a stirring shaft, a stirring rod, a water pump, a first connecting pipe, a second connecting pipe, a shell, ahose, a partition plate, a rotating rod, a driven gear, a second motor, a driving gear, a rotating disc, a mounting frame, a spraying pipe and a spraying head, the problem that the efficiency is lower due to the fact that traditional mushrooms are manually sprayed with fertilizer can be effectively solved, and through the device, the fertilization area of the mushrooms can be effectively increased, meanwhile, the labor intensity of workers is reduced, the fertilization time is saved, and the purpose of convenient operation is achieved.