In this paper, a new controlled release system of superoxide dismutase was developed by electrospun composite fibers. Highly loading efficacy of sod from 85.6 to 98.0% was achieved. The superoxide dismutase can be released from the system for 234 h, and obvious initial burst release of superoxide dismutase in vitro was not observed. In vitro release rate of superoxide dismutase in the first 66 h basically is faster than the corresponding rate at a later stage. Antioxidant activity of the released superoxide dismutase was still high, and it remained stable during the preparation by electrospinning and release experiment. We hope this composite system be used as an implanted form, in the treatment for several disease involved with the superoxide radical in the future.