The invention discloses a negative oxygen ion-release health cashmere composite fiber. The fiber is prepared from 30-40 parts by weight of cashmere fibers, 13-16 parts by weight of polyacrylonitrile fibers, 15-18 parts by weight of soybean fibers, 16-20 parts by weight of bombax ceiba fibers, 0.3-0.6 parts by weight of sodium laurate, 2-3 parts by weight of tourmalinite powder, 1-2 parts by weight of diisocyanate, 5-8 parts by weight of isopropyl palmitate, 10-20 parts by weight of agricultural emulsifier No.600, 3-5 parts by weight of ginkgo leaf, 2-4 parts by weight of lotus leaf, 1-2 parts by weight of radix bupleuri, 100-110 parts by weight of 1-ethyl-3-methylimidazolium acetate, 95-105 parts by weight of 1-allyl-3-methylimidazolium chloride, 20-30 parts by weight of an auxiliary agent and a proper amount of water. The polyacrylonitrile fibers, soybean fibers, bombax ceiba fibers and cashmere fibers are immersed in the Chinese herbal medicine-modified anti-pilling auxiliary agent and modified tourmalinite powder is added into the mixture so that the cashmere composite fibers are prepared. The cashmere composite fiber can effectively release active negative oxygen ions, has the advantages of antibiosis, mildew resistance and wear resistance, reduces cashmere surface friction, improves cashmere fabric anti-pilling performances, is soft, slip and fluffy, has warming effects and further improves a cashmere added value.