Improvement of elevated-temperature performance of LiL02Cr0. 1MnLg04 cathode material by silicious sur- face modification was studied. The Lil0Cr0. 1lMnl. 904 cathode material was treated by silanes coupling agent and then heated at 580℃ to remove organic material. The structures of the modified and unmodified Li1. 02Cr0. lMn1. g04 were characterized by SpectraPlus, SEM and XRD. The results show that the surface layer of Li1. 02Cr0. 1Mnl. 904 ma- terial is found to be rich in silicious compound. X-ray diffraction show that all the samples have perfect spinel structure. The electrochemical characterization of modified Li1. 02Cr0. 1Mnl904 cathode material was tested. The cycle stability of charge/discharge at 55℃ is improved. The results of the charge/discharge curves show that the modi- fied LiCralMnl. 904 has better performance than those unmodified according to the inhibition of decline of reversible capacity of spinel Li1. 02Cr0. 1Mnl. 904. Therefore, cycle performance is improved so obviously that 86. 03% of the initial capacity is preserved after 100 cycles.