Poly(acrylonitrile-co-acrylic acid) (PANCAA) was synthesized and fabricated into nanofibrous membranes by an electrospinning technique. Scanning electron microscopy revealed that membranes composed of uniformly thin and smooth nanofibres were obtained under optimized processing parameters. Surface modification with chitosan on these nanofibrous membranes was accomplished by a coupling reaction between the carboxylic groups of PANCAA and the primary amino groups of chitosan. Fluorescent labelling, weight measurement, FT-IR/ATR spectroscopy, and X-ray photoelectron spectroscopy (XPS) were used to confirm the modification process and determine the immobilization degree of chitosan. Platelet adhesion experiments were further carried out to evaluate the hemocompatibility of the studied nanofibrous membranes. Preliminary results indicated that the immobilization of chitosan on the PANCAA nanofibrous membranes was favourable for platelet adhesion.