Poly(vinyl alcohol) (PVA) sponges with different chitooligosaccharide (COS) content were prepared for wound-dressing application. The morphological structure of PVA sponges was observed by scanning electron microscopy. As the concentration of COS-loaded PVA sponge increased, the average pore size of sponge decreased and the release rate of COS from the sponge also slightly decreased. The accelerating effect of the COS-loaded PVA sponges on open wound healing in rats was investigated by macroscopic examination and measurement of wound area. The COS-loaded sponges were found to be very effective as a wound-healing accelerator in the early stage of wound healing. The wound treated with the COS-loaded PVA sponge was almost reepithelialized, granulation tissues in the wound were considerably replaced by fibrosis at 8 days after initial wounding. The COS-loaded PVA sponge was considered to be a suitable wound-healing formulation due to its easy preparation and high effectiveness.