The invention provides a high-power semiconductor laser fiber coupling device and belongs to the technical field of laser. The beam quality and the output power of a fiber-coupled semiconductor lasercannot be easily improved effectively through the prior art in the field, so that application of a high-power semiconductor laser is greatly limited. According to the high-power semiconductor laser fiber coupling device, high-power and high-beam quality laser output is obtained by adopting three laser stack array modules through beam combining, beam expanding and focusing separately; overlapping beam combining is achieved by adopting output beams of laser stack arrays through 45-degree reflection; the positions of focusing waists of combined beams in fast-axis and slow-axis directions are consistent through convergence adjustment of a cylindrical lens in the slow-axis direction; and a coupling light path is turned back through two reflectors, so that the whole light path structure is compactly arranged.