An absorbable sponge, composed of gelatin and alginate, was prepared by new crosslinking method that improved the efficiency of crosslinking. The crosslinking degree was characterized by trinitrobenzenesulfonic acid (TNBS) assay. A water uptake ability test, in vitro drug release and collagenase degradation tests, and an in vivo animal test were employed to confirm the applicability of this gelatin-alginate sponge as a wound dressing material. As the alginate content in the sponge increased, the porosity increased, resulting in an enhanced water uptake ability. Sponges loaded with silver sulfadiazine or gentamicin sulfate slowly released drugs for up to four days. The crosslinked sponge resisted in vitro collagenase digestion for up to three days. An in vivo animal test using witar rat showed rather good wound healing effect of gelatin-alginate sponge containing AgSD than vaseline gauze in our full-thickness skin defect model.