The invention relates to a high-duty cycle beam-combination system based on a birefringent crystal. The high-duty cycle beam-combination system comprises a polarization rotating system, a collimator arrangement system and a high-duty cycle synthetic system. Firstly, the polarization control on incident beams is realized by utilizing the polarization rotating system, subsequently, reasonable spatial arrangement is performed on beams which need to be spliced by the collimator arrangement system, and finally, high-duty cycle aperture splicing is performed on the whole array by the high-duty cycle synthetic system. The high-duty cycle beam-combination system is suitable for large-size laser synthesis, the laser power density of each beam-combination device can be effectively reduced, the synthetic aperture of the whole coherent synthetic system is increased, and remote transmission of synthetic beams is facilitated. According to the high-duty cycle beam-combination system, high-duty cycle aperture filling of any beam and any arrangement structure array can be realized.