This paper introduces the implementation and evaluation of a real-time terahertz communication system based on the PXIe platform. The system employs direct sequence spread spectrum (DSSS) communication technology and quadrature phase shift keying (QPSK) modulation, using a single-antenna point-to-point configuration. The system's performance was tested over a distance range of 0–100 cm. The experimental results show that, compared to non-spread spectrum signals, the bit error rate (BER) is significantly reduced after using direct sequence spread spectrum (DSSS) under the same signal-to-noise ratio conditions. For example, at a signal-to-noise ratio of 58.6 dB, the bit error rate was reduced by 50% after spreading. These findings highlight the great potential of direct sequence spread spectrum technology in future ultra-high-speed communication systems.