A curable thermosetting resin composition, including a multicomponent copolymer and an epoxy resin. The multicomponent copolymer is a ternary or quaternary copolymer having structural units selected from the group consisting of unit (I), unit (II), unit (III) and (IV). The structural unit (I) is the structural unit (II) is the structural unit (III) is and the structural unit (IV) is where m, n, r and s are natural numbers denoting the molar fraction of corresponding building blocks in the copolymers respectively, R is selected from the group consisting of hydrogen, aromatic group and aliphatic group, and AR is an aromatic group; and the epoxy resin is one or more selected from a group consisting of aromatic epoxy compound, alicyclic epoxy compound and aliphatic epoxy compound.