The LiMn2O4 thin films composed of nanoparticles were synthesized by sintering electrodeposited Mn3O4 precursor on the Au substrate, and the electrochemical properties were investigated. The electrochemical performance was dependent on the film thickness. For the thinner LiMn2O4 films, cycling in the voltage range of 4.3 V–3.4 V resulted in superior rate performance, that is almost 100% of discharge capacity compared with that at 20 times of discharge current density, and good stability without capacity loss until 500 cycles. CV and EIS measurements revealed that LiMn2O4 thin film has good electric contact with substrate and high lithium diffusion coefficient of 10−9–10−11 cm2 s−1 could be obtained.