Objective: To explore the cytotoxicities of MWCNT to the mesothelial cells and screen the changes of microRNA profile after exposure to MWCNT. Methods: A LDH method was used to test the cytotoxicities of MWCNT to MeT-5A cell lines. And then the differentially expressed miRNAs between mesothelioma cells and normal mesothelial cells were selected from previous work of research group. Among the significant expression changed miRNAs, 5 were verified by RT-qPCR in mesothelioma cells. The same five ones were further tested in MeT-5A cells exposed to 10 μg/cm2 MWCNT for 8, 24, 48, 72 h by RT-qPCR. Target genes of 5 miRNAs were predicted using Targetscan and miRanda softwares. David6.7 was used to perform GO enrichment and KEGG pathway analysis of target genes. All the data were analyzed by one-way ANOVA and Dunnett-T test in SPSS17.0. Results: After 24 h exposure to MWCNT, cell proliferation was significantly suppressed at more than 20 μg/cm2 concentration. Among the differentially expressed miRNAs, 5 were chosen to further vestified, namely hsa-miR-155 (up-regulated) , hsa-miR-30 d-5p, hsa-miR-34c-5p, hsa-miR-28-5p and hsa-miR-324-5p (down-regulated) , which were consistent with the miRNA array results. The 5 miRNAs also had the same expression changes in MeT-5A cells after exposure to 10 μg/cm2 MWCNT for different time periods. The potential target genes of the 5 miRNAs may be AKAP13, CCND3, Twist and E-Cadherin, which mainly involved in TGF-β signal pathway, small cell lung cancer, etc. Conclusion: MWCNT could induce to MeT-5A cells, and also cause miRNA expression changes. The differential changed miRNAs may involve in cancer related signal pathways.