The invention discloses a SiC staple fiber composite, a composite cladding tube and a preparation method of the composite cladding tube and solves the problems that preparation processes and prepared cladding tubes have more defects due to adoption of existing preparation methods of SiC/SiC composite cladding tubes. The SiC staple fiber composite is prepared from a suspension, a binder, a plasticizer and a defoaming agent, wherein the suspension comprises 50wt%-65wt% of mixed powder, 30wt%-45wt% of a solvent and 0.5wt%-5wt% of a dispersant; the mixed powder consists of a SiC material and a sintering aid, the SiC material consists of SiC fibers and SiC particles in the volume ratio being (20-40): (60-80); the sintering aid accounts for 4wt%-8wt% of the SiC material; the length of the SiC fibers is 4-8 mm. the prepared composite cladding tube has the characteristics of high compactness, good air tightness, high strength and toughness, high heat conductivity, excellent corrosion resistance and the like.