Abstract: Objective：To investigate the relationship between CD3+ T cells and CD8+ T cells and clinicopathological features of oral lichen planus (OLP). Methods：We detected the expression of CD3 and CD8 in 79 cases of OLP and 10 cases of normal oral mucosa by using semi-quantitative immunohistochemistry. The relationship between the expression of these T cells and clinicopathological parameters were analyzed statistically. Results：The expression of CD3 and CD8 were positive in OLP and negative in normal oral mucosa. The infiltration of CD3+ T cells had no relationship with gender, age or the location of OLP, but it was closely related to the development of erosion in OLP, which was statistically significant (P＜0.05). However, there was no relationship between the CD8+ T cells and gender, age, location or erosion of OLP. Conclusions：The infiltration of CD3+ T cells affected the incidence of erosion in OLP.