Conversion-type materials are an appealing alternative to conventional intercalation compounds as cathode materials for sodium ion batteries, due to their high capacities. In this paper, we report for the first time that carbon-coated copper phosphate (Cu3(PO4)2/C) can be used as a novel high-capacity cathode for rechargeable Na batteries. Cu3(PO4)2/C shows a reversible capacity up to 290mAhg−1 at a current of 20mAg−1and 190mAhg−1 at 400mAg−1, with capacity retention of 210 and 160mAhg−1 respectively after 30 cycles. The detailed sodium storage mechanisms were studied by employing ex-situ XRD, HR-TEM, solid-state NMR and XAFS techniques. The results clearly indicate that Cu3(PO4)2 can transform into Na3PO4 and Cu particles after discharge. Furthermore, Cu can react with Na3PO4 to form copper phosphate and NaxCuyPO4 in the charge process, determining the rechargeability of Cu3(PO4)2.