A series of vanadium modified carbon coated lithium iron silicate (Li₂Fe_1-xV_xSiO₄/C) composites were prepared by sol-gel precursor and solid-state reaction using ammonium metavanadate (NH₄VO₃) as a vanadium source material. The effects of vanadium content (x), sucrose amount (y), sol-gel time (t) and type of carboxylate acid on crystal structure, surface morphology, elemental composition and electrochemical performance of Li₂Fe_1-xV_xSiO₄/C composites were investigated through orthogonal design experiments. The preparation parameters were optimized to be x=35%, y=80%, t=2 h and use of citric acid as a pH regulator. The initial discharge capacity of 216.7 mAh/g (corresponding to 1.30 moles per formula unit) was achieved at 0.1C and room temperature with the Li₂Fe_0.65V_0.35SiO₄/C composite synthesized under the abovementioned optimized condition. A mixed Pmn2₁ and P2₁ phase was identified as the main structure, while metallic iron and lithium silicate (Li₂SiO₃) as the impure phases. The elemental analysis result revealed that 10.7% carbon was introduced. The elemental vanadium was detected by performing energy dispersive X-ray spectroscopic (EDX) analysis.