Abstract: The dispersing of MgO nano-particles on the surface of the activated carbon fiber(ACF) was affected by chemical precipitation.The optimized conditions for even dispersing of MgO nano-particles on the surface of ACF were obtained through analyzing different concentrations of NaOH and duration of reaction.The photographs of scanning electronic microscopy(SEM) showed that the size of MgO particle was ranging from(50 nm) to(100 nm.) The X-ray photoelectron spectroscopy(XPS) analysis demonstrated MgO presence on the surface(of ACF.)