The invention relates to a self-repair anti-oxidation silicon carbide casting material and a preparation method thereof. According to the technical solution, 75-95 wt% of silicon carbide, 1-8 wt% of carbon black, 0.1-8 wt% of monatomic silicon powder, 0.5-6 wt% of silica powder and 0.1-4 wt% of monatomic zirconium are used as raw materials, and a water reducing agent accounting for 0.1-0.3 wt% of the raw materials is added into the raw materials and mixed uniformly, so as to obtain a premix; and then silica sol accounting for 5-15 wt% of the raw materials is added into the premix, and the silica sol and the premix are stirred uniformly to obtain the self-repair anti-oxidation silicon carbide casting material. The prepared self-repair anti-oxidation silicon carbide casting material has the characteristics of excellent medium- and high-temperature mechanical properties, high thermal conductivity, strong oxidation resistance, good thermal shock stability, long service life, energy conservation and environment friendliness.