Aiming at the problem that the performance of free space optical communication links is easily affected by atmospheric turbulence, a multiple-input multiple-output (MIMO) polarization-coding method suitable for free space optical communication is constructed in this paper. The rapid construction of the polarization code adopts the universal partial sequence method, polarization-coding, modulation, and MIMO technologies are jointly optimized; the simulation analysis is performed under the atmospheric turbulence channel. The experimental results show that MIMO polarization-coding methods can improve system performance while maintaining low complexity under different construction methods and coding schemes. Under strong turbulence conditions and a bit error rate of 10^-4, compared to the Monte Carlo method, the coding gain of the partial sequence method is about 0.2 dB. The computational complexity of offline construction is negligible. However, under strong and weak turbulence conditions, compared with the single-input single-output (SISO)-polar method, the coding gain of the MIMO (2×2)-polar method is about 1.1?1.6 dB, which has obvious diversity advantages.