The present invention provides a silicon-carbon composite which contains a body having a core-shell structure and a polymer modification layer. The core of the body contains a silicon-containing particle. The shell of the body is a carbon encapsulation layer. The polymer modification layer is located on the external surface of the shell of the body and encapsulates the body. The polymer modification layer comprises a polymer selected from the group consisting of polyester, polyfluorocarbon, polyvinyl alcohol, polyacrylic acid, cellulose and a combination thereof.