The invention discloses an energy-saving type air-jet loom weft yarn inserting system, which comprises a centralized air source air supplementing system and a piston type air compressor weft yarn inserting air supply system, wherein the centralized air source air supplementing system comprises a centralized air source, a filter, a first multi-mesh seat, an air supplementing pressure regulating valve, an air supplementing electromagnetic valve, a normal sprayer throttle valve, a yarn passing sprayer throttle valve, a normal sprayer and a yarn sprayer, the piston type air compressor weft yarn inserting air supply system comprises a loom body, a piston type air compressor, a main spraying weft yarn inserting mechanism and a sub spraying weft yarn inserting mechanism, the air supplementing regulating valve is connected with the air supplementing electromagnetic valve, the air supplementing electromagnetic valve is respectively connected with the main spraying weft inserting mechanism and the sub spraying weft inserting mechanism, the main spraying weft inserting mechanism comprises a main spraying regulating valve, a main air bag, a main spraying electromagnetic valve, a second multi-mesh seat and a main sprayer, the sub spraying weft yarn inserting mechanism comprises a sub air bag, a sub spraying electromagnetic valve and a sub sprayer, and the normal sprayer is also connected with the second multi-mesh seat. The weft yarn inserting system provided by the invention has the advantages that the energy consumption can be reduced, and the stable and sufficient air quality can be realized for ensuring the weft yearn inserting capability.