The invention relates to the technical field of cleaning of silicon carbide wafers, in particular to a pre-cleaning method before epitaxy of the silicon carbide wafer. The pre-cleaning method before epitaxy of the silicon carbide wafer comprises the following steps: immersing a selected silicon carbide substrate in solution formed by mixing H2SO4 and H2O2 to boil and then washing with de-ionized water; immersing the substrate into molten mixed solution of NaOH and Na2O2 again to boil, washing with the de-ionized water and drying for later use. After the silicon carbide substrate is subjected to the epitaxy, the base plane dislocation density is reduced to be below 100/cm<2>; the method is simple, the repeatability of the process is good, and the method is suitable for industrial production.