The invention discloses an automatic fixed-point fertilization starting hammer which comprises an impact pneumatic hammer, a connecting rod, a drilling pin and a pneumatic conversion valve. The drilling pin is fixedly mounted below the connecting rod, a connecting sleeve is arranged at the bottom of the impact pneumatic hammer, the top of the connecting rod is movably mounted in the connecting sleeve, a hollow gas-pressure conveying pipeline is arranged inside the drilling pin, a discharge outlet is formed in the bottom of the drilling pin, a feed pipe is arranged on the connecting rod and is connected with the gas-pressure conveying pipeline and the pneumatic conversion valve, a high-pressure gas feed pipe, a fertilizer feed pipe and a comprehensive discharge pipe are arranged on the pneumatic conversion valve, and the comprehensive discharge pipe is connected onto the feed pipe of the connecting rod. The automatic fixed-point fertilization starting hammer has the advantages that drilling, soil loosening and fertilization operation can be carried out at fixed-point locations for urban trees under combined effects of the impact pneumatic hammer, the drilling pin and the pneumatic conversion valve, and the automatic fixed-point fertilization starting hammer is simple in structure, convenient to operate and high in fertilization efficiency and is small in occupied area during fertilization operation.