The invention provides a preparation method of a nano silicon carbide material with high metal content, an electrode prepared by the nano silicon carbide material with high metal content, and a whole silicon carbide lithium secondary battery. Raw materials used in the preparation method include an amorphous silicon carbide powder, polysiloxane, lithium polyacetylene and a metal mixed powder; the metal mixed powder is formed by mixing a metal lithium powder, a metal aluminum powder, a metal beryllium powder, a metal magnesium powder and a metal titanium powder, at the same time, a dielectric barrier discharge plasma process and a high-energy ultrafast laser technology are adopted, and the content of metals in the obtained nano silicon carbide material is high. The whole silicon carbide lithium secondary battery assembled by the electrode prepared by the nano silicon carbide material with high metal content has the advantages of long life, high capacity and good cycling performance, the first Kulun efficiency reaches 99.9%, the discharge platform is 4.1-3.5 V, the specific capacity reaches 2450 mAh/g, the discharge energy density reaches 1600-2000 Wh/kg, the power density reaches 1600-2000 W/kg, and the cycle period can reach 20000 times.