Chitosan-polyethylene oxide (CS/PEO) complex nanofibers were prepared by dissolving CS and PEO powder in 90% aqueous acetic acid. The weight ratio of CS to PEO was set at 90:10. Considering the morphology and electrospinning efficiency of nanofibers, influences of spinning solution concentration, spinning voltage, receiving distance, feeding speed, and environmental humidity on the fibers morphology were investigated respectively. Also, the optimal spinning parameters were given.