The invention relates to a pump shaft structure. The pump shaft structure comprises a pump shaft and a motor shaft arranged in the pump shaft in a sleeve mode, a key groove is formed in the motor shaft, a key is arranged in the key groove, and a fixing device sequentially penetrates through the pump shaft, the key and the motor shaft to fix the pump shaft and the motor shaft together. the motor shaft, screws, the pump shaft and the key provided in the pump shaft structure are all standard parts except the pump shaft, the motor shaft, the screws and the key are standard parts, and the pump shaft is made of stainless steel, the motor shaft is embedded in a pump shaft end hole, the motor shaft and the pump shaft are fixed through the key in the key groove in the shaft, and the pump shaft, the motor shaft and the key are fastened together through the screws. According to the pump shaft structure, compared with a traditional shaft structure, the shaft structure is safer and more reliable, convenient to machine and disassemble, stable in operation and high in universality, the total length of the shaft can be effectively shortened through the structure, operation is stabler and lasting, cost is reduced, and meanwhile the service life of the whole pump and quick-wear parts of the pump is prolonged.