Lichen planus is a relatively common chronic inflammatory disease of the skin, mucous membranes, nails and hair. Oral lichen planus (OLP) is common mucosal conditions with an unknown etiology. OLP develops in any area of the oral mucosa, especially in the buccal mucosa, tongue, gingiva and lips. A 26-year-old female was consulted from department of otorhinolaryngology with 4-year-history of OLP diagnosed by punch biopsy. Physical examination revealed painful erythematous plaques and erosions with white reticulated patches on dorsal surface of the tongue and white linear streaks on right buccal mucosa. The patient had been treated with tetracycline mouth rinse for erosions. The clinical manifestations had been repeated wax and wane. Treatment with 0.1% topical tacrolimus led to improvement of the lesions. However, because of the difficulties of applying the ointment on the scattered lesions on the oral cavity, we decided to use tacrolimus as mouth rinse. The topical medication was prepared by diluting one 1mg capsule of tacrolimus in 50mL of water. The patient did once daily mouth rinse for 30 minutes and washed it out. After two weeks, the size of the lesions had been decreased. The sensation of mouth burning and tingling was also disappeared. No adverse effects were observed. Herein, we report the case of the effects of tacrolimus mouth rinse in the treatment of OLP.