LiMnBO3 and its carbon coated material LiMnBO3/C were synthesized by a microwave method. The influences of sintering temperature and feed composition on the structure and the morphology of materials were investigated. XRD, SEM and HR-TEM were used to characterize the structure and the morphology of the materials. The electrochemical properties of materials were tested by constant charge-discharge and electrochemical impedance spectroscopy. The results show that LiMnBO3 has a hexagonal crystal structure (h-LiMnBO3). The good crystalline structure with small grain size can be obtained under the reaction conditions of 750 oC, 25 min and nLi:nB:nMn=1:1:1(molar ratio). The charge-discharge capacity and the conductivity of the carbon coated material are enhanced after carbon coating. The initial discharge capacity of LiMnBO3/C is 50.3 mAh/g