Objective To explore the expression of microRNA (miR)-27b in the brain tissue of hypertensive intracerebral hemorrhage (HICH) rats and its effect on the biological functions of astrocytes.Methods Fifteen healthy WKY rats served as the control group. Fifteen spontaneously hypertensive rats served as the HICH group. Rats in the HICH group were injected with autologous blood into the brain to construct a HICH model. The control group underwent sham operation but did not inject autologous blood. The brain tissue damage and apoptosis were detected by HE staining and TUNEL staining. The expression of miR-27b was detected by RT-qPCR. Astrocytes were divided into NC, miR-27b mimic group, and miR-27b inhibitor group. According to the group, the miR-27b mimic or miR-27b inhibitor plasmids were transfected to overexpress or inhibit the level of miR-27b. The levels of miR-27b and the levels of cell proliferation and apoptosis in each group of cells were detected.Results Significant damage to the brain tissue of hemorrhage in the HICH group. The apoptosis index (35.91 ± 3.24) and the expression level of miR-27b (3.45 ± 0.48) in the HICH group were significantly higher than those in the control group (2.75 ± 0.36, 1.00 ± 0.12) (P < 0.05). The miR-27b level of the miR-27b mimic group was significantly higher than that of the NC group, the proliferation activity was significantly lower than that of the NC group, and the apoptosis rate was significantly higher than that of the NC group (P < 0.05). The miR-27b level of the miR-27b inhibitor group was significantly lower than that of the NC group, the proliferation activity was significantly higher than that of the NC group, and the apoptosis rate was significantly lower than that of the NC group.Conclusion miRNA-27b is significantly increased in the brain tissue of HICH rats, inhibiting the proliferation of astrocytes and promoting their apoptosis.