Abstract: The purpose of this study was to observe the growing and healing of free gingival graft in animal experiments. Results indicated that the epithelium of the free graft degenerated and subsequently desquamated in the early healing phase. The connective tissue of the free gingival graft grew to form new attached gingiva after revascularization, reepithelialization, and a fibrous union with the underlying connective tissue bed, thus increasing the width of attached gingiva of the recipient area. This study provides a histological basis for the clinical use of this operation to treat gingival recession.