Abstract: A polarization code cascade space-time coding scheme for multiple-input and multiple-output power line communication systems is proposed to address the problem of poor system BER performance due to strong channel fading and great noise interference in power line communication. The information source is constructed as a polarization code by Gaussian, and then the polarization code is modulated into a symbolic and space-time block code for cascading. The simulation results show that the system BER performance of the polarization code cascade space-time block coding scheme is better than that of the space-time coding scheme, with a gain of about 7.2 dB in a power line impulse noise environment with a BER of 10-4 in the multi-input and multi-output power line communication system. When the system BER is 5×10-4, the system gain of the polarization code cascade space-time block coding scheme is about 0.2 dB, compared with the Turbo code cascade space-time coding scheme. By reducing the number of weak paths and pulse noise intensity, the cascade coding scheme shows a better anti-interference ability, and the system coding gain increases by a range of 0.2 dB to 0.5 dB more when the BER is below 10-3. In addition, due to the characteristics of polarization codes, the system BER performance can be further improved by decreasing the code rate or increasing the code length of the cascade coding.