Abstract: Porous phenolic resin-based carbon microspheres were prepared by inverse emulsion polymerization, followed by carbonization at 800℃ for 1 h and KOH activation at 800℃ for 1 h with a KOH/coke mass ratio of 4. Thermal setting phenolic resin in ethanol was used as one phase and a mixture oil of silicone oil and heat transfer oil as the other phase in the inverse emulsion polymerization. The performance of the porous spheres as electrode materials in supercapacitors was investigated. Results indicate that the size and morphology of the spheres are mainly determined by the mass ratio of silicone oil to heat conduction oil, the mass ratio of alcohol to phenolic resin and the stirring speed. The heat transfer oil with alkyl benzene size chains interacts with phenolic resin by a π-π interaction, which is beneficial for the formation of microspheres. The porous spheres prepared under the optimum conditions have a high specific capacitance of 206 and 134 F/g at current densities of 1 A/g and 20 A/g, respectively in a 6 M KOH electrolyte. The good capacitive and rate performance can be ascribed to the high specific surface area and the pore structures.