Fiber coupling is difficult due to the uneven beam parameter product between the vertical and horizontal axes of semiconductor lasers. A beam shaping technique based on the combination of the internal total reflection and polarization surface of a stepped prism is proposed to achieve filling the dark area of the beam and polarization merging, as well as enabling the polarization plane to be multiplexed and the utilization rate of the polarization plane to be increased. The proposed technology can couple three groups of stacked array semiconductor lasers into a single fiber, in which the center diameter is 200 µm, and the numerical aperture is 0.22. The simulation results indicated that the output power of 1099 W and optical-optical conversion productivity of 85.8% were achieved.