An in situ polymerization assisted fast sol–gel method was introduced to synthesize high performance Li3V2PO4/C (LVP/C) cathode material. The crystal structure, surface morphology and electrochemical performances of the LVP/C samples sintered at different temperatures were investigated. The composite sintered at 750°C exhibits the highest specific discharge capacity of 119.02mAhg−1 (440.35Whg−1) at 10C rate. The Li+ diffusion coefficient ranges from 10−6 to 10−8 cm2 s−1 based on different scanning rates and the electronic conductivity is about 10−5 Scm−1. For comparison, an ex situ polymerization method was also employed to obtain the LVP/C composite. A novel charge/discharge testing mode was designed to investigate the electrochemical behavior of the as-prepared LVP/C composite for practical application in electric vehicle cells. The obtained high power density and the special testing mode prove the LVP/C composite would be a promising candidate for the electric vehicle application and deserves further investigation.