An air feeding device of an air circuit system of a workover rig is applied to feeding air to the air circuit system of the oil field workover rig. An inverter is connected with an air pressure controlling and adjusting device through a conducting wire; the air pressure controlling and adjusting device is connected with an AC (alternating current) electric machine through the conducting wire; the AC electric machine is connected with an air compressor; the air inlet of the air compressor is connected with a filter; the air outlet of the air compressor is connected with a first manual exhaust-valve; the outlet end of the first manual exhaust-valve is connected with the inlet of a check valve; the outlet of the check valve is connected with a second manual exhaust-valve; the pipeline of the second manual exhaust-valve is connected with a dryer; the outlet of the dryer is connected with an overflow valve; and the air outlet of the overflow valve is connected with a gas tank. The air feeding device of the air circuit system of the workover rig has the benefits that independent air feeding to the air circuit system of the workover rig is achieved, the engine is not required to be specially started for the operation of the air feeding device, and the energy-saving effect is excellent; and the air feeding device is particularly suitable for being mounted on the electric drive workover rig for use, and has excellent energy-saving effect.