Objective：To investigate the relationship between CD3+ T cells and CD8+ T cells infiltration and atypical hyperplasia in oral lichen planus (OLP) , which will provide a new direction for the clinical diagnosis and immunotherapy of OLP. Methods：Immunohistochemical semi-quantitative method was used to detect the CD3+ T cells and CD8+ T cells infiltration in 79 cases of OLP patients, meanwhile 10 cases of normal oral mucosa as a control. The relationship between these T cell infiltration and atypical hyperplasia in OLP was analyzed by statistical methods. Results：CD3+ T cells and CD8+ T cells were negatively expressed in normal oral mucosa, but were positively expressed in 79 cases of OLP. The infiltration of CD3+ T cells and CD8+ T cells had no relationship with gender, age or the location of OLP, but they were closely correlated with the atypical hyperplasia of OLP（P<0.001 and P=0.002, respectively）, the infiltration of CD3+ T cells were positively associated with the infiltration of CD8+ T cells（r=0.498，P<0.001）. Conclusions：The infiltration of CD3+ T cells and CD8+ T cells is closely related to epithelial dysplasia, which affects the occurrence and development of OLP.