In this work, poly(amide imide) (PAI) fibers containing various silicon content ratios were prepared for the precursor of carbon fibers by electrospinning method from 25 wt.% PAI in dimethylformamide (DMF) solution. The fibers were stabilized and then subsequently carbonized in a flow of nitrogen to obtain porous Si/carbon fibers. The morphologies and the crystalline structures of the Si/CFs were characterized by scanning electron microscopy (SEM) and X-ray diffractometer (XRD). The electrochemical behaviors of the Si/CFs were observed by cyclic voltammetry tests. The experimental results indicated that the Si/CFs exhibited convoluted structure and wrinkled surface morphology. The silicon particles had a uniform diameter of approximately 1 μm. And the electrochemical activity of the Si/CFs was gradually improved due to the buffering effect of the large Si volume expansion and shrinkage. In addition, the fibers exhibited large accessible surface area, high reversible capacity, and relatively good cycling performance at high current densities. Consequently, it was found that the introduction of silica could affect the electrochemical properties of the CFs, and the Si/CFs might have potential applications for various fields of electrochemical materials.