The invention discloses a damp-proof emulsion paint preparation method, and relates to the technical field of chemical industry. The damp-proof emulsion paint preparation method comprises the following steps that 1, two thirds by weight of deionized water, one third by weight of defoaming agent, a dispersing agent, bentonite, titanium dioxide and ground calcium carbonate are added into a stirring machine, and stirring is conducted at the rotating speed of 2,000 revolutions/minute for 35 min; 2, AMP95, a coalescing agent, propylene glycol, preservative and the deforming agent left in the first step are added into the stirring machine in the first step, and stirring is conducted at the rotating speed of 800 revolutions/minute for 12 min to 20 min; 3, vinyl acetate, superabsorbent resin and deionized water left in the first step are added into the stirring machine in the second step, stirring is conducted at the rotating speed of 800 revolutions/minute for 30 min, and damp-proof emulsion paint is obtained. According to the damp-proof emulsion paint preparation method, the problem that existing emulsion paint is poor in damp-proof function can be solved.