The invention discloses toughening-modified UV light curing epoxy acrylate resin and a preparation method thereof. The preparation method comprises the following steps: mixing dihydric alcohol, acid anhydride and an antioxidant together, and stirring for a reaction at 75 to 85 DEG C until the acid value of a reactant reaches 140-160 mgKOH/g to obtain a first reaction liquid; adding a catalyst andepoxy resin into the first reaction liquid, and controlling the reaction temperature to be 75-85 DEG C until the acid value of the reactant is less than 3 mgKOH/g to obtain a second reaction liquid; and adding acrylic acid, a catalyst and a polymerization inhibitor into the second reaction liquid, and controlling the reaction temperature to be 80-100 DEG C until the acid value of the reactant is less than 5 mgKOH/g to obtain the toughening modified UV light curing epoxy acrylate resin. The toughening-modified UV light curing epoxy acrylate resin not only has good adhesion and surface hardness,but also has excellent flexibility and impact resistance.