Abstract: Objective To explore the effect of hemodialysis therapy on removal of serum microRNA-92a and its mechanism on injury of vascular endothelial cells. Methods The serum samples of patients with chronic kidney diseases in XI'AN GaoXin Hospital treated with long-term hemodialysis were collected before and 6h after dialysis, and serum miR-92a level, BUN, Scr and hsCRP were measured. The cultured endothelial cells were stimulated with the serum samples from patients with chronic kidney diseases before and after dialysis, so as to observe the expression changes of miR-92a and its target gene eNOS. Results There was no significant difference in serum miR-92a level (1.48±0.24 vs 1.20±0.18, P=0.356) and hsCRP (7.6±2.4vs 7.5±3.1, P=0.862) before and after hemodialysis. Serum BUN (26.4±8.8 vs 8.3±2.3, P<0.01) and Scr (926.3±178.1 vs 312.3±141.2, P<0.01) levels were decreased significantly by hemodialysis therapy. The further in vitro cell assay, RT-PCR, confirmed that compared with the normal healthy human serum, the serum from chronic kidney disease patients before and after dialysis could promote expression of miR-92a n in the cultured HUVEC (P<0.001). RT-PCR and Western Blot test demonstrated that the expression of its target gene eNOS was significantly reduced (P<0.001).Conclusions Serum miR-92a level does not obviously decrease after hemodialysis. miR-92a can reduce the expression of eNOS in endothelial cells, which may be part of the reason why dialysis can maintain renal function but cannot prevent against cardiovascular complications.