This study aimed to explore the expression changes of microRNA (miR)-140-5p and miR-370 in nephroblastoma and its effect on the proliferative ability of nephroblastoma WT_CLS1 and SK-NEP-1 cells.The expression levels of miR-140-5p and miR-370 was detected by quantitative real-time PCR (qRT-PCR) in cancer tissues and normal adjacent tissues which were collected from 60 patients with nephroblastoma. Expression vectors of miR-140-5p and miR-370 were constructed, and transient transfection of human nephroblastoma cell lines WT_CLS1 and SK-NEP-1 was carried out in vitro. There were three groups of the two genes: Blank cell group (blank group); Gene transfection group (miR-490-5p group, miR-370 group); and No-load transfection group (NLTF group). The proliferative ability of WT_CLS1 and SK-NEP-1 cells was detected by MTT assay.The results of miR-140-5p and miR-370 detected by qRT-PCR showed that in cancer tissues the expression level of miR-140-5p was significantly lower than that in adjacent tissues, and the level of miR-370 was significantly higher than that in adjacent tissues, and the difference was statistically significant (p<0.001). The proliferation of WT_CLS1 and SK-NEP-1 cells in miR-140-5p group was significantly lower than that in NLTF group (p<0.05), while the proliferation of WT_CLS1 and SK-NEP-1 cells in miR-370 group was significantly higher than that in NLTF group (p<0.05).miR-140-5p is lowly expressed and miR-370 is highly expressed in nephroblastoma tissues; miR-370 can promote the proliferation of WT-CLS1 cells in nephroblastoma, and miR-140-5p can inhibit their proliferation and it may become a new target for the treatment of nephroblastoma in the future.