Environmentally-friendly adhesive

The invention discloses an environmentally-friendly adhesive, and relates to the technical field of adhesives. The problem of low adhesive strength of starch adhesives is solved. The adhesive is prepared from, by weight, 20-30 parts of starch, 100-150 parts of water, 1-10 parts of 1 mol/L hydrochloric acid, 0.04-0.06 part of 0.1% potassium permanganate, 2-4 parts of sodium hypochlorite, 1-10 partsof a 4% sodium hydroxide solution and 1-2 parts of a cross-linking agent. A preparation method of the environmentally-friendly adhesive comprises the following steps: 1) weighing the starch, adding the starch into the water, performing water bath heating to 50-60 DEG C while stirring, dropwise adding the 1 mol/L hydrochloric acid, and performing uniform stirring; 2) adding the 0.1% potassium permanganate, performing a reaction for 10-15 min, adding the sodium hypochlorite, and performing a reaction for 10-20 min; 3) rising the temperature to 60-70 DEG C, adding the 4% sodium hydroxide solution to adjust the pH value