The invention discloses a carbon based bimetallic composite material. The composite material includes a carbon based shell, the inner surface of the carbon based shell is compounded with a sulfide ofa transition metal A, and the outer surface is compounded with an oxide of a transition metal B. The transition metal A and the transition metal B are selected from different metals. The invention also discloses a preparation method of the carbon based bimetallic composite material, and the method includes: subjecting a mixed solution salt containing a salt of the transition metal A, a salt of thetransition metal B, an organic ligand and alcohol to hydrothermal reaction at 60-180DEG C so as to obtain bimetallic MOF; and mixing the obtained bimetallic MOF with sublimed sulfur, then conductingroasting in a protective atmosphere at 300-800DEG C, thus obtaining the carbon based bimetallic composite material. In addition, the invention also includes application of the composite material as anOER electrocatalyst. The invention provides an electrocatalyst with a brand-new structure. The material has excellent OER catalytic performance. Under an electric current density of 10mA / cm<2>, the oxygen evolution potential is close to 0.55V, and under an overpotential of 320mV, the TOF can reach 34.7s<-1>.