The invention discloses an in-situ repairing method of microcracks generated after silicon carbide ceramic is ground. The method is characterized in that the ground silicon carbide ceramic is heated for temperature rise, so that the surface of the silicon carbide ceramic and the surfaces of the cracks have an oxidation reaction, and a glass phase repairing film used for filling and splicing the cracks and repairing the surface cracks left by grinding machining is formed on the surface of the silicon carbide ceramic and the surfaces of the cracks. By means of the method, within a short time, through surface oxidation, the continuous and compact glass phase repairing film can be quickly formed to fill and splice the cracks to repair the surface cracks left by grinding machining, and thus thematerial strength is increased.