Preparation method of flame-retardant epoxy resin

The invention relates to the technical field of flame-retardant materials, in particular to a flame-retardant epoxy resin preparation method which comprises the following raw materials: epoxy resin, a curing agent, a flame retardant and an accelerant. The flame-retardant epoxy resin is characterized by comprising the following raw materials in parts by weight: 50-60 parts of epoxy resin, 5-10 parts of a curing agent, 10-15 parts of a flame retardant and 0.1-0.3 part of an accelerant, the epoxy resin curing agent is prepared by adding a dihydroxyl spiro pentaerythritol diphosphate compound into epoxy resin and mixing, when the dihydroxyl spiro pentaerythritol diphosphate compound curing agent is used, reactive components in the curing agent have active groups such as hydroxyl and amino, and participate in the curing reaction of the epoxy resin, so that the curing effect is improved. The compatibility of the epoxy resin and the flame retardant is increased, so that the tensile strength, bending strength and imp