The invention discloses an inherently safe double-layer composite clad tube for nuclear fuel, a fuel rod and a preparation method, including an inner tube arranged in an inner layer and an outer tube compounded in the outer layer of the inner tube. The inner tube adopts SiC composite material, and the outer tube adopts FeCrAl based alloy or NiCr based alloy. The double-layer composite clad tube of the invention has excellent high temperature steam oxidation resistance, water side corrosion resistance and high temperature strength. Under normal working conditions, the water side corrosion resistance is superior to the traditional zirconium alloy cladding and the single SiC composite cladding, so that the fuel can be used for a longer life, higher fuel consumption or higher temperature; At the same time, under severe accident conditions, the high temperature mechanical properties of cladding materials are improved. Under ultra-high temperature (about 1200 ℃), the structural integrity of fuel rods can be ensured, and the ability of fuel rods to resist LOCA accidents can be improved.
