Square tube derusting and polishing machine, also known as four side square tube derusting machine or angle iron channel steel derusting machine, has four grinding heads up, down, left and right for grinding and polishing at the same time. Each grinding head has an independent control switch, and the grinding head motor is equipped with overload protection device respectively. It can be used for surface polishing and wire drawing of titanium nickel alloy, rare earth alloy, precious metal alloy, copper aluminum alloy strip, stainless steel strip and carbon steel strip with different thickness on both sides, so it is also called plane wire drawing polishing machine. The material of pipe fittings requiring polishing and derusting and wire drawing is different, the effect of wire drawing polishing and derusting is also different, and the polishing and wire drawing wheel is also different.