Spherical LiFePO₄ /C  doped with Mg²⁺ (namely LiMg_x Fe_1－x PO₄ /C) was prepared by means of the spray drying-carbonthermal reduction,with citric acid,ferrous oxalate and magnesium acetate as the carbon source,the iron source and the magnesium source,respectively.Then,the effects of Mg²⁺ doping on the structure and electrochemical performance of the prepared LiFePO₄ /C material were investigated.The results indicate that (1) LiMg_x Fe_1－x PO₄ /C possesses a hollow ball-shaped structure and a high specific capacity; (2) the crystal struc- ture of lithium iron phosphate keeps unchanged at a low Mg²⁺ dosage; and (3) LiMg_0.04 Fe_0.96 PO₄ /C possesses the best charge/discharge performance.For instance，its initial discharge capacities are 149. 0,145. 6,141. 3,132. 6 and 123. 3mAh/g at the rates of 0. 2C,0. 5C，1. 0C,2. 0C and 5. 0 C,respectively; and the capacity retention ra- tio of LiMg_0.04 Fe_0.96 PO₄ /C at 1. 0C keeps more than 97. 3% after 100 charge-discharge cycles.