Objective · To observe the influence of keratinized mucosa on peri-implant soft tissue health and stability after implant treatment among patients with chronic periodontitis. Methods · Fifty-eight patients with chronic periodontitis (158 implants) who received implant treatment were enrolled Aug. 2010 to Nov. 2013. The soft tissue conditions were observed, the peri-implant disease rate and mucosa recession rate were compared between patients in different keratinized mucosa groups. Results · The differences of rates of peri-implant mucositis and peri-implatitis between the narrow keratinized mucosa (NKM) group and wide keratinized mucosa (WKM) group were not statistically significant (P0.862, P0.625). The effects of the width of the keratinized mucosa on modified plaque index and modified bleeding index were not significant (P0.826, P0.913). When the width of the keratinized mucosa ≥ 2 mm, the recession of mucosa is not evident. The recession incidence of the thick and wide mucosa was 12.86%, which was significantly lower than that of the thin and wide mucosa (33.33%) and that of thick and narrow mucosa (40.63%) (P0.049, P0.002). Conclusion · Keratinized mucosa has a positive effect on peri-implant tissue stability among patients with chronic periodontitis susceptibility. The keratinized mucosa withsufficient width can prevent the mucosa recession.