The invention relates to the field of shoes, and provides an antibacterial foaming insole and a preparing method thereof. The defects in the prior art that insoles have a poor antibacterial effect anda single function are overcome. The antibacterial foaming insole is prepared from, by weight, 35-38 parts of natural rubber, 20-25 parts of butadiene rubber, 15-20 parts of a wear-resisting agent, 14-19 parts of a mildew inhibitor, 40-45 parts of talcum powder, 1.3-1.5 parts of zinc oxide, 14-15 parts of a first accelerant, 20-25 parts of titanium dioxide, 20-23 parts of a second accelerant, 15-20 parts of an anti-yellowing agent, 20-23 parts of an oxidizing agent, 12-13 parts of a foaming agent, 60-70 parts of purified water, 5-8 parts of radix sophorae flavescentis liquid, 3-7 parts of cortex phellodendri liquid, 4-6 parts of radix scutellariae liquid, 5-8 parts of rhizoma polygoni cuspidati liquid, 4-6 parts of climbing groundsel herb, 4-6 parts of fructus cnidii liquid, 10-20 parts oftea polyphenol and 10-15 parts of far-infrared powder.