Circulating microRNAs (miRNAs) can be employed as biomarkers to diagnose liver and other diseases. Noninvasive approaches are needed to complement and improve the current strategies for screening for biomarkers liver cirrhosis. We determined whether the serum levels of miRNAs can distinguish between chronic hepatitis B (CHB) and CHB-induced cirrhosis (HBC) and investigated the potential mechanisms involved. We found that serum miR-27a was significantly up-regulated in HBC, distinguishing HBC from CHB and healthy controls (Ctrl) (P < 0.0001, the area of under the curve (AUC) = 0.82 and 0.87, respectively). Specifically, when miR-27a was combined with miR-122, HBC was differentiated from CHB with an AUC=0.94. The serum miR-27a level in HBC patients with hepatic decompensation was significantly higher than that in patients with compensated HBC (P=0.0009). MiR-27a was also significantly up-regulated in the serum of rats with DMN-induced liver cirrhosis compared to that in saline-treated rats (P < 0.0001). Furthermore, the down-regulation of miR-27a inhibited the proliferation and overexpression of miR27a in activated hepatic stellate cells (HSCs) through the up-regulation of a-SMA and COL1A2 expression by targeting PPAR., FOXO1, APC, P53 and RXRa. Our study demonstrated that circulating miR-27a can be used as a predictor for the activation of HSCs and the occurrence and development of HBC.