〔Abstract〕 Objective To study the effect of miR-34 b-5 p Up-regulation on the invasion of diffuse large B cell lymphoma and the RhoA/ROCK signaling pathway. Methods SU-DHL-4 cells were selected for study in diffuse large B lymphoma lines. A blank control group, an empty vector transfection group, and a miR-34 b-5 p transfection group were established. The expression of miR-34 b-5 p was detected by qRT-PCR. Cell proliferation, apoptosis and invasive were tested by colony formation assay, flow cytometry and Transwell test respectively. Western blot was used to detect the proteins expression levels of E-cadherin, N-cadherin Vimentin, RhoA and ROCK. Results miR-34 b-5 p expression was significantly up-regulated in cells transfected with miR-34 b-5 p. miR-34 b-5 p overexpression inhibited SU-DHL-4 cells proliferation, enhanced SU-DHL-4 cells apoptosis, reduced SU-DHL-4 cells invasion, and inhibited the RhoA/ROCK signaling pathway. Conclusion miR-34 b-5 p overexpression inhibits the growth and motility of diffuse large B cell lymphoma and the expression of RhoA/ROCK signaling pathway.