A series of spinel Li4Ti5O12 samples were synthesized via a composite molten-salt method (CMSM) using the mixtures of LiCl and KCl with different L values (L is defined as the molar ratio of LiCl:KCl) as the reaction media. It is found that the melting point of the composite molten salt can effectively influence the formation of particles, and leads to different electrochemical performances of the as-prepare Li4Ti5O12. The investigations of X-ray diffraction (XRD), particle size distribution (PSD), Brunauer–Emmet–Teller (BET) surface area, and scanning electron microscopy (SEM) indicate that the as-prepared Li4Ti5O12 with L =1.5 is a pure phase, and has uniform homogeneous octahedral shape particles, rather narrow PSD, and high BET surface area. Electrochemical tests show that the optimized Li4Ti5O12 with L =1.5 has an initial discharge capacity of 169mAhg−1 and an initial charge–discharge efficiency of 94% at 0.2C rate, and achieves good rate performances from 0.2C to 5C.