The invention discloses a hardware spraying 
machine with 
polishing and 
rust removing functions and a using method, and belongs to the technical field of spraying devices. The hardware spraying 
machine comprises a 
workbench, a vertical plate is fixedly connected to the upper surface of the 
workbench, four air cylinders are fixedly connected to the left side face of the vertical plate, and a 
rust removing mechanism is installed at the telescopic end of each air cylinder; and a spraying mechanism and an 
air drying mechanism are installed on the upper surface of the 
workbench. According to the 
machine, by arranging the 
rust removing mechanisms, a rotary disc, a motor, a first rotary shaft, the air cylinders and a gear, the motor drives the first rotary shaft and the rotary disc to rotate so as to drive a hardware 
water pipe body to rotate, circular tables are rotated to adjust the positions of the two circular tables, the circular tables push rust removing blocks to move away from a square 
barrel to proper positions, the telescopic ends of the air cylinders stretch and retract, therefore, the rust removing mechanisms are driven to move left and right in the hardware 
water pipe body to remove rust on the inner wall of the hardware 
water pipe body, and the rust on the inner wall of the hardware water 
pipe body is removed in a physical rust removal mode.