In this paper the influences of the time-varying plasma and magnetized time-varying plasma on the communication performance are investigated. Using a 5.8 GHz microwave source, the electron density and collision frequency of the time-varying glow discharge plasma are measured. An experimental platform is set up to test the bit error rates (BERs) of a variety of the modulation signals after going though the time-varying plasma channel. The experimental results show that the binary phase shift keying (BPSK) modulation signal has a minimal communication BER. Meanwhile, the variations of L-band BPSK and S-band QPSK (quadrature phase shift keying) signal's eye diagram and the constellation diagram, and the variation of energy after a magnetized plasma are observed. Compared with the un-magnetized situation, the magnetized plasma communication performance is greatly improved and the BER becomes much lower. The results prove that the magnetic field can effectively relieve the amplitude modulation and phase modulation caused by the plasma channel.