The invention provides a water transfer printing activating agent and belongs to the technical field of water transfer printing. The water transfer printing activating agent is composed of, by weightpercentage, 70-80% of ethylene glycol monoethyl ether acetate, 6-10% of cyclohexanone, 9-15% of 783 isophorone, 3-6% of ethylene glycol monobutyl ether and 0.8-1.2% of n-butyl alcohol. The water transfer printing activating agent has the advantages of low toxicity and environmental friendliness and has the advantage of high rate of finished products when used for water transfer printing of automobile interior products.