A new LiMnPO4 based material, LiMn0.8Fe0.19Mg0.01PO4/C, is synthesized by a solid state method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical test. The obtained LiMn0.8Fe0.19Mg0.01PO4 crystals with 8wt.% carbon coating are mainly 100–500nm in size, and aggregate into microparticles around 3–5μm. The electrochemical test demonstrates that the obtained LiMn0.8Fe0.19Mg0.01PO4/C has high capacity, good cycleability and quite excellent rate capability in spite of its larger size and less carbon coating as compared to those reported in the previous works. When discharged at a high rate of 10C, the obtained LiMn0.8Fe0.19Mg0.01PO4/C can still deliver a capacity of 115mAhg−1. The results prove that the LiMn0.8Fe0.19Mg0.01PO4/C is a very promising cathode material for lithium ion batteries.