Abstract: A method of preparing LiFePO4/Li3V2(PO4)3 composite cathode materials and their applications as cathode materials for lithium ion batteries are disclosed. The preparation method includes the following steps: (A) providing a mixture of iron powder, lithium salt, vanadium salt, and a phosphate salt whereafter these compounds are dissolved into a mixed acid solution; (B) drying the solution in order to obtain precursor powders; and (C) heating the precursor powders at a temperature ranging between 400 and 1000° C. to form LiFe1-y?Vy?PO4/Li3V2-y?Fey?(PO4)3 composite powders. Alternatively, prepare the composite cathode by preparing olivine LiFe1-y?Vy?PO4 and monoclinic Li3V2-y?Fey?(PO4)3 powders as in previous procedures followed by mixing adequately. The low cost of iron powder thus facilitates to prepared composite cathode materials exhibiting higher electrical conductivity and superior cycling performance at high C rates than those of olivine LiFe1-y?Vy?PO4 and monoclinic Li3V2-y?Fey?(PO4)3.