The present invention relates to an epoxy resin varnish composition with high glass transition temperature for laminate plate, wherein the resin composition comprises: (A) a new dihydrobenzoxazine thermosetting resin obtained by reacting compounds: (a) phenolic products from reaction of di- or multifunctional epoxy resin and di-functional phenolic compounds; (b) mono- or di-functional primary amines; (c) di-functional phenols; and (d) formaldehyde or paraformaldehyde, (B) one or more epoxy resins, (C) novolac resin curing agents, and (D) curing promoters. For the epoxy resin varnish composition, crosslinking density of resin is increased due to using modified dihydrobenzoxazine thermosetting resin with multiple functional groups, so that mechanical strength and heat resistance of the obtained substrate are remarkably improved, and solubility problem of dihydrobenzoxazine in solvent is solved to greatly elevate production efficiency. The epoxy resin varnish composition according to the present invention, which is useful as high performance electronic materials, is of high glass transition temperature (Tg), low water absorption and excellent heat resistance, and is qualified for UL94 V-0 Flammability Test.