Manganese compound with evident toxicity is widely employed as the contrast medium for clinical examinations such as magnetic resonance imaging(MRI).In the present work,a feasible way with the application of vacuum impregnation and rotary evaporation was proposed to introduce manganese chloride hydrate into the inner cavities of template-synthesized carbon nanotubes(CNTs),and then a process of alkali treatment was used to liberate the loaded CNTs from the template.It is notable that the alkali attack in the presence of residual oxygen also resulted in a series of changes in chemical compositions of guest substances,and the ultimate compound of manganese was found to be manganese oxide(Mn3O4)by X-ray diffraction and transmission electron microscopy.Determinations of energy dispersive spectrum under scanning electron microscopy showed a high-content filling(more than 50 wt%)of Mn3O4 in the loaded CNTs.This work developed a feasible and convenient way for the encapsulation of guest substances to reduce bio-toxic effects.