Abstract： Objective To determine the effect of microRNA(miR)?191 on the invasion and migration of tongue squamous cell carcinoma cells. Methods Realtime PCR was used to examine the expression of miR?191 in tongue squamous cell carcinoma cell lines Cal?27,CTST?1 and SCC9 and normal oral epithelial HOK cells. miR?191 inhibitors were transfected into tongue squamous cell carcinoma cells. The cell proliferation was measured by MTT assay,and the cell invasion and migration were measured by Transwell chamber. It was predicted that the transfected phospholipase Cδ1(PLCD1)may be the target gene of miR?191. Luciferase reporting system was used to identify the targeting relationship. miR?191 inhibitors and PLCD1 siRNA were co?transfected into tongue squamous cell carcinoma cells to determine cell proliferation,invasion and migration. Results The level of miR?191 in tongue squamous cell carcinoma cell lines Cal?27,CTST?1 and SCC9 was higher than that in normal oral epithelial HOK cells. The expression level of miR?191 in tongue squamous cell carcinoma cells transfected with miR?191 inhibitors decreased,and the cell proliferation,invasion and migration ability decreased. miR?191 targeted and regulated PLCD1. The level of PLCD1 protein in tongue squamous cell carcinoma cells co?transfected with miR?191 inhibitors and PLCD1 siRNA decreased,whereas the cell proliferation,invasion and migration increased. Conclusion Down?regulation of miR?191 targeted PLCD1 expression may inhibit invasion and migration of tongue squamous cell carcinoma cells.