To　investigate　the　influence　of　radiolysis　on　kinetics　and　factors　of　dimethyl　phthalate(DMP),　the　aqueous　DMP　solution　is　degraded　by　1.8　MeV　E-beam,　following　pseudo-first-order　kinetics.　The　rate　constant　of　DMP　degradation　decreased　exponentially　with　increasing　initial　DMP　concentration.　The　DMP　is　favorably　degraded　by　radical　scavengers　under　its　low　concentration　and　alkaline　condition.　At　high　doses,　the　DMP　is　attacked　by　e(aq)(-)　and　center　dot　OH,　producing　monomethyl　phthalate,　phthalate　acid,　and　a　series　of　aliphatic　carboxylic　acids,　which　are　completely　mineralized　into　H2O　and　CO2.