The utility model discloses a compound cross arm strain insulator tower in two return circuits of transmission line, its characterized in that: including body of the tower (1), to installing down in cross arm (3) on ground wire cross arm (2), the wire, the wire under cross arm (4) and the wire cross arm (5) in proper order on body of the tower (1) follow, in cross arm on the wire (3), the wire under cross arm (4) and the wire cross arm (5) all include with metal cross arm (6) that body of the tower (1) links to each other, metal cross arm (6) both ends symmetry formula is provided with combined material cross arm (7). The utility model provides a pair of compound cross arm strain insulator tower in two return circuits of transmission line, the line channel width is less, and is handsome in appearance, and convenient to use is nimble, can effectively reduce construction investment, reduction line channel width and tower head height, reduces the engineering construction external resistance, and is little to the environmental impact.