The invention discloses an adhesive for the sole of a leather shoe and a preparation method thereof. The adhesive comprises the following raw materials by weight: 10 to 30 parts of white glue, 4 to 16 parts of carboxymethylcellulose sodium, 4 to 5 parts of titanium dioxide, 3 to 9 parts of polyoxyethylene, 3 to 9 parts of natural particles, 15 to 25 parts of ultramarine, 3 to 9 parts of potassium chloride, 4 to 8 parts of an osmotic agent JFC, 1 to 9 parts of a dispersing agent, 1 to 3 parts of casein, 3 to 10 parts of a foaming agent, 3 to 9 parts of stearic acid and 30 to 35 parts of soft water. The adhesive for the sole of the leather shoe is low in toxicity and friendly to environment and is an environment-friendly adhesive; and the raw materials of the adhesive are easily available and low in cost. According to the method, the usage amount of macromolecular materials in the adhesive is reduced and the usage amount of natural particles is increased, so shoe material infiltration performance of the adhesive is improved. Since titanium dioxide has good weatherability, the prepared adhesive has stable chemical properties and is not prone to denaturation and viscosity reduction.