The invention discloses a preparation method of a grading porous carbon material, and belongs to the technical field of carbon material preparation. The method comprises the following steps: getting cheap coal tar pitch as the carbon source, nanometer iron sesquioxide as a template, and potassium hydroxide as an active agent; grinding the three components; transferring the mixture into a corundum crucible; and heating in an atmosphere furnace, so as to obtain the grading porous carbon material for electrochemical electric container, wherein the grading porous carbon material has the specific surface area between 1157 to 1330m<2>/g, the total pore volume ranges from 0.69 to 1.35cm<3>/g, the average aperture ranges from 2.39 to 4.05nm; the ratio of the pore volume of the non-micropore to the total pore volume ranges from 37.7 to 65.9%; and the yield of the porous carbon ranges from 32.6 to 52.2%. The grading porous carbon material prepared via the method provided by the invention serves as the electrode material of the electrochemical electric container, and is good in stability and excellent in comprehensive performance.