The invention discloses a manganese dioxide@ manganese dioxide submicron sphere and a preparation method therefor. The submicron sphere adopts a bell structure with oxygen vacancy microcosmically, wherein a shell layer is assembled by manganese dioxide nanoparticles with oxygen vacancy while the core is porous manganese dioxide. The manganese dioxide@ manganese dioxide submicron spherical materialwith the oxygen vacancy bell structure has the characteristics of a porous structure, a large specific surface area, high conductivity and structural stability, and can be used for an electrode material of a supercapacitor; the specific capacitance can reach 452.4Fg<-1> at the current density of 1Ag<-1>; the specific capacitance still can be as high as 316.1Fg<-1> at the increased current densityof 50Ag<-1>, so that high rate capability is shown; and when the cycle performance is tested at the current density of 10Ag<-1>, the capacity retention ratio can reach 92.2% after 10,000 cycles, so that high cycle stability is represented.