The rod mill is driven by the motor through the reducer and the peripheral big gear reducer, or the low-speed synchronous motor directly through the peripheral big gear reducer to drive the cylinder to rotate. Proper grinding medium - steel bar is installed in the barrel. Under the action of centrifugal force and friction force, the grinding medium is lifted to a certain height and falls down in a throwing or discharging state. The material to be milled continuously enters the cylinder from the ore feeding mouth, is crushed by the moving grinding medium, and the product is discharged out of the machine through the overflow and continuous ore feeding force for the next process.