The invention discloses a light-cured three dimensional printing material and a preparation method thereof. The light-cured three dimensional printing material comprises, by mass, 40-45 parts of polyester modified epoxy acrylate, 8-12 parts of cycloaliphatic epoxy resin, 8-10 parts of trihydroxymethylpropyl trimethylacrylate, 16-20 parts of 1,6-hexanediol diacrylate, 2-8 parts of triethyleneglycol divinyl ether, 1.5-2 parts of isopropylthioxanthone, 1.5-2 parts of 2-phenyl-2,2-dimethylamino-1-(4-morpholinylphenyl)-1-butanone, 1.5-2 parts of a reactive tertiary amine co-initiator, 0.5-2.7 parts of 4-isobutylphenyl-4'-methylphenyliodonium hexafluorophosphate, 0.5-2 parts of an anthraquinone derivative, 0.5-2 parts of a promoter and 4-8 parts of a flexibilizer. Shaped parts made by using the light-cured three dimensional printing material have the advantages of low shrinkage, high toughness and high shaping precision.