The invention relates to a safe and environment-friendly type natural stone waterproof alkali-resistant backing adhesive and a preparation method of the safe and environment-friendly type natural stone waterproof alkali-resistant backing adhesive. The backing adhesive comprises the following components by weight: 4-6 parts of liquid mixture and 4-6 parts of powder mixture, the liquid mixture comprises the following components by weight: 380-420 parts of acrylic emulsion, 95-105 parts of lithium silicate aqueous solution, 1-3 parts of sterilizing agent, 1-3 parts of defoaming agent, and 450-550 parts of water, the powder mixture comprises the following components by weight: 430-480 parts of kaolin, 280-320 parts of heavy calcium carbonate powder, 230-270 parts of snowflake white powder, 1-3 parts of water reducing agent, and 1-3 parts of cellulose; and the various components in the powder mixture are respectively added into the liquid mixture in the preparation process. Compared with the prior art, the lithium silicate aqueous solution and the acrylic emulsion are compounded, the kaolin, the heavy calcium carbonate powder and the snowflake white powder are used as powder materials, the prepared backing adhesive is high in bonding strength, water resistance and alkali resistance, the phenomena of efflorescence, saltpetering and water spotting of the natural stone are solved fundamentally, and the backing adhesive is safe and environment-friendly.