The invention relates to a carbonaceous material wide-temperature-range antioxidant repair coating and repairing and preparing methods thereof. Silica sol, phenolic resin or silicon resin serves as a binder of the repair coating, silicon, carbide and oxide serve as high-temperature-resisting filler, and the materials are fully dispersed and mixed to prepare a boron-silicon repair material. By the adoption of repair material coating and low-temperature curing technologies, in-situ low-temperature quick repair of an antioxidant coating defect area can be achieved. The process is simple, period is short, coating repair can be achieved at low temperature, and high-temperature thermal treatment is not needed. A formed repair layer can be well bonded with a base material and an original coating, and antioxidant function can be realized within a wide temperature range (500-1600 DEG C).