Air compressor with noise reduction assembly

The air compressor comprises a containing box and a supporting assembly, the two ends of the containing box are arranged in a penetrating mode, inserting plates are vertically connected to the two ends of the containing box in an inserted mode, the supporting assembly is horizontally arranged on the bottom face of the containing box, the supporting assembly comprises an upper supporting frame and a lower supporting frame, the upper supporting frame is horizontally fixed to the bottom face of the containing box, and the lower supporting frame is horizontally fixed to the bottom face of the containing box. An insertion cylinder is vertically fixed on the upper support frame in a penetrating manner, a lower support frame is horizontally arranged right below the upper support frame, an insertion rod is vertically fixed on the top surface of the lower support frame, a spring is vertically sleeved on the insertion rod, two ends of the spring are respectively fixed on the horizontal planes of the adjacent upper supp