Abstract: To investigate the effect of miR-802 on insulin secretion by islet β cells and its mechanism, miR-802 was overexpressed or knocked down in primary islet cells and Min6 cells via transfecting miR-802 mimic and miR-802 inhibitor, respectively. The effect of miR-802 on insulin secretion was detected by ELISA. The target gene of miR-802 was confirmed by miRNA target gene database prediction, luciferase report and Western blot. The function recovery experiment was carried out to clarify the mechanism of miR-802 regulating β cell secretion of insulin. The results showed that overexpression of miR-802 in islet primary cells and Min6 cells inhibited insulin secretion. qPCR and Western blot showed that miR-802 inhibited insulin secretion by inhibiting the transcription and translation of the target gene, hepatocyte nuclear factor 1β(Hnf1B).