A high-power horizontal array type semiconductor laser comprises an upper pressing block, a lower pressing block, laser units, electrode connecting pieces, a positive electrode piece, a negative electrode piece, outer cooling pieces and protective plates; the upper pressing block and the lower pressing block are disposed on the two sides of the laser units and are symmetrically arranged; the laserunits is arranged between the two pressing blocks, and each laser unit comprises a chip, an inner cooling piece, an insulation piece and a negative electrode connection piece; the electrode connecting pieces are arranged at the two sides of the laser units; the positive electrode piece is arranged at the bottom surface of the laser unit at one end; the negative electrode piece is arranged at thetop surface of the laser unit at the other end; the outer cooling pieces are arranged at the outer sides of the electrode connecting pieces at each side, and the protective plates are respectively patched at one sides of the upper pressing block and the lower pressing block and are symmetrically arranged. The electrode connecting pieces of the invention are difficult in manufacturing process, arelow in manufacturing cost, good in heat dissipation performance and high in heat exchange efficiency, and ensure that the laser is in a high-performance operation state.