Microwave-assisted solvothermal method has been developed for synthesizing LiMn0.7Fe0.3PO4 cathode materials with an olivine structure. The obtained LiMn0.7Fe0.3PO4 nanorods were characterized by X-ray diffraction, scanning and transmission electron microscope, Brunauer-Emmett-Teller surface area measurements, and electrochemical tests. Electrochemical tests clearly indicate that the as-made LiMn0.7Fe0.3PO4 nanorods exhibit two redox activities of Fe3+/Fe2+ and Mn3+/Mn2+ couple at galvanostatic charge-discharge process, which is due to the coexistence of Mn2+ with Fe2+ at 4c sites. The as-synthesized materials have high energy density, excellent rate capability and cycling stability.