The invention relates to a 
microwave preparation method of an anti-oxidation 
coating made of a carbon-based material, in particular to a substrate material which may be a carbon material, a C / C 
composite material or a C / SiC 
composite material. In the invention, 
slurry prepared by using Si compounds is coated on the carbon-based material, which is subjected to surface treatment, by a 
brush or immersion, then the carbon-based material is buried in 
graphite powder in a 
corundum crucible, the 
corundum crucible is placed in microwaves to be heated, the pre-heating, heating and temperature preservation are performed by stepwise regulating the power of a 
microwave oven, and thus, an anti-oxidation single-layer 
coating is obtained; on this basis, a 
composite coating of oxides, silicides and the like can be obtained. In the invention, microwaves act directly on the carbon-based material and the carbon-based material, after absorbing the microwaves, generate heat raises the temperature to a required temperature, so that the 
coating and a substrate are bonded and a protective coating with high protective performance is obtained; and as aluminum 
powder is added as a SiC 
sintering aid, the compaction of the SiC is promoted by the 
silicon aluminum 
alloy produced by the low-melting-point aluminum and part of 
molten silicon.