Polyacrylonitrile (PAN)/Si composite fibers (electrodes) with flexibility were fabricated using an elec-trospinning method and then Si-embedded carbon (Si/C) fibers were prepared by carbonizing the composite fibers at 800, 900, and 1000°C. Si particles were distributed in the interior and exterior of entangled PAN fibers. After carbonization, the structure of electrodes was preserved but the diameter of fibers was decreased owing to the release of component elements constituting PAN such as nitrogen and oxygen. Crystalline Si particles existed in carbon fibers with both amorphous and crystalline phases. As carbonization temperature increased, the carbon content and the crys-tallinity of carbon increased. The electrode carbonized at 1000°C with the lowest charge transfer resistance exhibited the best electrochemical properties in terms of capacity, coulombic efficiency and cycle life.