The invention discloses a side-leakage-prevention sanitary towel protective pad. The side-leakage-prevention sanitary towel protective pad comprises a sanitary towel body, a permeation-prevention area is arranged on the sanitary towel body, a diversion groove is formed in the inner side of the permeation-prevention area, an absorption area is arranged at the inner side of the diversion groove, an infrared anion chip is arranged inside the absorption area, a peripheral diversion groove is formed in the bottom of the permeation-prevention area, a permeation-prevention groove is formed in the outer side of the permeation-prevention area, protective wings are arranged at the two sides of the sanitary towel body, an absorption layer is arranged on the sanitary towel body, a diversion layer is arranged at the bottom of the absorption layer, a water-locking layer is arranged at the bottom of the diversion layer, and a leakage-prevention layer is arranged at the bottom of the water-locking layer. The sanitary towel body is provided with the permeation-prevention area of a dam-shaped protective fence structure and the absorption layer, multiple protections are achieved, and side leakage can be effectively prevented. The protective wings achieve the effect of fixing the sanitary towel, and the prevention of menstruation side leakage is facilitated. The absorption layer is high water-absorption resin, the adsorption effect is better, the water-locking layer constituted by short fluff cotton can effectively absorb menstruation, and a water-repellency material can prevent permeation of the menstruation.