The invention provides an epoxy resin composition, comprising (A) 100 parts by weight of the epoxy resin; (B) 20-100 parts by weight of a cyanate ester resin containing a polyphenylene oxide structure; (C) 10-50 parts by weight of a styrene-maleic anhydride (SMA) copolymer; (D) 5-50 parts by weight of a maleimide resins, and optionally at least one of the following components of (E) an inorganic filler, (F) a catalyst, (G) a phenolic resin, (H) a flame retardant and (I) an adhesion agent. The epoxy resin composition contains specific components and proportions to achieve low dielectric constant, low-dielectric loss, high glass-transition temperature and no halogen; the printed circuit board can be made into a half-cured film or a resin film, and further the object of applying the epoxy resin composition to copper foil substrates and printed circuit boards can be reached.