The invention discloses sterilization moldproof aqueous putty powder and a preparation method thereof, and relates to the field of coatings. The sterilization moldproof aqueous putty powder is prepared from the following components: 25-50 parts of natural epidesmine powder, 20-35 parts of ash calcium powder, 5-10 parts of silicon dioxide dihydrate, 0.8-1.5 parts of cellulose, 2-5 parts of rubber powder, 0.5-1 part of pigment and 0.05-0.3 part of triclosan. The preparation method comprises the following steps: sequentially adding three main materials, namely, natural epidesmine powder, ash calcium powder and silicon dioxide dehydrate into a stirring machine, stirring to mix uniformly, sequentially adding four secondary materials, namely, cellulose, rubber powder, pigment and triclosan of requested mass into the stirring machine, and continuously stirring to sufficiently mix the materials, thereby obtaining the sterilization moldproof aqueous putty powder. The sterilization moldproof aqueous putty powder has the functions of sterilization, mold resistance, humidity adjustment, and air purification.