The invention provides a foamy carbon based heat-insulation 
composite material with light weight and high strength. The foamy carbon based heat-insulation 
composite material with light weight and high strength is characterized by comprising a base material foamy carbon, an SiC 
coating and reticulated SiC nanowires, wherein a foamy 
carbon skeleton is coated with the SiC 
coating; three-dimensional pores are filled with the reticulated SiC nanowires, 
porosity is 90%-95%, average 
pore diameter is 50 nm-500 nm, 
apparent density is 0.05-0.2 g / cm<3>, and 
compressive strength is 5-15 MPa. Foamy carbon is flexible foamy carbon and is prepared from 
melamine foam through high-temperature 
pyrolysis, the 
porosity is 99% or higher, and the average 
pore diameter is 20-50 mu m; the thickness of the SiC 
coating is 0.5-1 mu m, the 
diameter of the SiC nanowires is 50-300 nm, the average length is 30-50 mu m, and all the SiC nanowires are prepared with a 
chemical vapor deposition method. The light foamy carbon based heat-insulation 
composite material with high strength has the advantages as follows: 1, the foamy 
carbon skeleton is coated with SiC, so that 
oxidation resistance of the composite material is improved; 2, the foamy 
carbon skeleton is coated with SiC, and mechanical properties of the composite material are improved accordingly; 3, internal pores of foam are segmented by the SiC nanowires, the internal 
pore diameter is reduced, and the heat 
conductivity of the composite material is reduced.