The invention relates to a stainless steel pipe inner surface cleaning machine and an operation method thereof. The stainless steel pipe inner surface cleaning machine comprises a U-shaped frame, a clamping device, an air cylinder, a generator motor, an iron shaft, three electromagnetic attraction blocks and three cleaning devices, wherein the air cylinder is installed on the rear side of the upper end of the U-shaped frame, the air cylinder is connected with the clamping device, the clamping device is installed at the lower end of the U-shaped frame, the clamping device is connected with a frame body of the U-shaped frame in a sliding fit mode, the generator motor is installed on the front side of the upper end of the U-shaped frame, the iron shaft is installed at the lower end of the generator motor, the iron shaft is located on the dead center position among the electromagnetic attraction blocks, the cleaning devices are evenly arranged on the exteriors of the electromagnetic attraction blocks, and limiting plates are symmetrically arranged at the upper end and the lower end of each cleaning device. The stainless steel pipe inner surface cleaning machine scrapes scrap iron and burrs on the inner surface of a stainless steel pipe through the cleaning devices, enables the electromagnetic attraction blocks to use magnetic force for attracting the scraped scrap iron, uses the air cylinder for driving the clamping device to move up and down, and meanwhile uses the generator motor for driving the cleaning devices to rotate, and then improves work efficiency.