Abstract: The invention provides a preparation method of shell-core type carbon-coated manganese and its alloy oxide nano-composite particles. Firstly, an automatic control DC arc metal nano-powder production equipment is used, proper amount of metal manganese or manganese alloy raw materials are added, and block metal manganese or manganese alloy raw materials are evaporated in a mixed atmosphere of a certain proportion of inert gas and carbon-containing gas to obtain carbon-coated manganese or carbon-coated manganese alloy nano-composite particle precursor. Then, the precursor was heated and oxidized in the reaction atmosphere to obtain carbon-coated manganese oxide or carbon-coated manganese alloy oxide nanocomposite particles. The nanocomposite particles prepared by this method have shell-core structure with graphite carbon as shell and manganese and manganese alloy oxide as core, and have two characteristics of electric double layer capacitance and pseudocapacitance, which greatly improves the capacity of supercapacitor electrode.