The invention relates to an inflammation preventing, disinfecting, heat rash eliminating and itch relieving aerosol and a preparation method thereof. The aerosol comprises a gas phase and a liquid phase, the gas phase is a propellent, the liquid phase comprises, by weight, 10-20 parts of lidocaine, 1-10 parts of chlorhexidine acetate, 0.1-3 parts of benzalkonium bromide, 10-30 parts of copovidone, 10-30 parts of isopropanol, 5-10 parts of ethyl acetate, 30-40 parts of polyethylene glycol, 30-40 parts of ethanol, a mass ratio of the gas phase to the liquid phase is 1:4-8, and the propellent is one or more of propane-butane, isobutene, tetrafluoroethane, heptafluoropropane and dimethyl ether. The inflammation preventing, disinfecting, heat rash eliminating and itch relieving aerosol has the efficacy of preventing inflammation and disinfecting, eliminating heat rash and relieving itches, and restoring sunburn, and has a good film forming performance; and test of multiple clinic research mechanisms shows that the aerosol has substantial curative effects on mild cuts, scratches, soft tissue injuries, burns, mosquito bites, pruritus and heat rash, so the aerosol has great promotion application values.