Keratinized mucosa in oral cavity plays an important role in periodontal health. The defect of keratinized mucosa may increase the risks of complication of oral implant surgery and restoration. Graft of keratinized tissue and connective tissue are still the gold standard for treating keratinized mucosa defect now. The current research focus on how to modulate non-keratinized mucosa to highly-efficient and minimally-invasive keratinized mucosa. Keratinocytes are critical components of oral mucosa and its final differentiation into keratinized mucosa is controlled by the connective tissue microenvironment involving a variety of molecules and ions. To fully understand keratinized differentiation of keratinocyte, this review focuses on its influence factors and possible mechanisms under the differentiation.