Mesocarbon microbeads (MCMB) powders were treated in Ar–H2–SF6 radio frequency inductively coupled thermal plasma. The structure, chemical composition and related electrochemical property changes have been studied. The results demonstrated that the active surface area has a great influence on the electrochemical properties of MCMB powder, and the specific irreversible capacity loss decays non-linearly with the increase of active surface area.