The high bandwidth capacity, high reliability, and low latency communication requirements of 5G/B5G mobile communication systems require more novel technology support. Millimeter wave (mmWave) has become one of the research hotspots of 5G/B5G mobile communication systems due to its rich spectrum resources and extremely high bandwidth capacity. Different from the past Internet architecture dominated by wired networks, the mobile Internet has become a fusion of wireless access networks and high-speed core networks, so the network transfer performance is facing huge challenges. However, the research work on the transfer performance of mmWave end-to-end communication is still relatively small and simulation experiments are basically used. In this study, we use the actual network devices to carry out experiments under real network environment to analyze the link bottleneck in the transfer process of 5G/B5G mmWave mobile network by measuring the basic transfer performance of 5G/B5G mmWave link and the end-to-end TCP transfer performance in the 5G/B5G mmWave mobile network. The results lay the foundation for designing mmWave end-to-end network transmission protocols and improving network transmission throughput.