Intra-body　communications　(IBC)　is　a　short-range　wireless　communication　technology,　which　has　been　included　as　the　third　physical　layer　in　the　IEEE　802.15.6　standard.　Up　till　the　present　moment,　it　is　difficult　to　achieve　a　high-data-rate　galvanic　coupling　IBC　system,　which　is　one　of　the　main　problems　limiting　the　development　of　implanted　medical　sensors.　In　this　paper,　the　modulation　scheme　of　differential　phase　shift　keying　(DPSK)　and　coherent　demodulation　method　of　Costas　loop　are　adopted　in　FPGA　to　design　a　galvanic　coupling　IBC　transceiver　system　with　low　coupling　amplitude　and　high　data　rate.　By　means　of　in　vivo　experiments,　the　data　acquisition　card　is　used　to　acquire　the　transmission　data　and　calculate　the　bit　error　rate　within　a　certain　range　of　signal-to-noise　ratio　(SNR).　The　system　achieves　reliable　transmission　in　the　human　body　at　a　data　rate　of　up　to　1　Mbps　under　a　low　coupling　amplitude,　which　provides　a　reference　for　the　future　development　of　IBC　in　the　wearable　or　implantable　medical　sensors.　©　2020　IEEE.