The invention provides a low-temperature SCR (Selective Catalytic Reduction) catalyst based on an active coke loaded active component and a preparation method of the low-temperature SCR catalyst. The catalyst is suitable for SCR reaction of nitrogen oxides under the condition of low temperature. A Mn and Ce composite oxide is loaded on an active coke particle with a relatively high special surface area and mechanical strength, so that the SCR reaction temperature is reduced, the adsorption capability and mechanical wear resistance of the catalyst are improved, and the whole sulfate resistance and regeneration capability of the catalyst are improved. The preparation method provided by the invention is simple in step, artful in process design and convenient for industrial production. The catalyst provided by the invention takes the active coke particle as a carrier on which the Mn and Ce composite oxide is loaded. Oxides of modified elements can also be loaded on the carrier of the catalyst, wherein the modified elements are selected from one or more of the following elements: Fe, Zr, Si, Ti, V, Mo, W, Cr, Au, Ag, Pt, Pd, Rh and Co.