Abstract: Based on polarization beam combination technology, system analysis and quantitative calculation of several main system errors in the process of beam combination are conducted to improve the combining efficiency. The results show that, compared to overlap error, tilt angle and absorption loss of the polarization beam combiner, the adjustment error of half-wave plate is the main factor causing the decline of combining efficiency. If the loss of polarization beam combiner is 0.015, the inclination of incident beams is 2, and the overlap error is 5%, the coherent polarization beam combining efficiency of sixteen beams can be controlled more than 92.5%. When the deviation of the optical axis of half-wave plates is 0.045 rad, even without other errors, the combining efficiency will drop below 74%.