OBJECTIVE To explore the improvement mechanism of proanthocyanidins on acute kidney injury （AKI） induced by gentamicin in rats. METHODS Gentamicin sulfate was injected intraperitoneally to construct the AKI rat model； the model rats were randomly divided into model control group， benazepril hydrochloride 5 mg/kg group （positive control）， proanthocyanidins 50 mg/kg group， proanthocyanidins 100 mg/kg group， and proanthocyanidins 200 mg/kg group， with 10 rats in each group； in addition， 10 normal rats were selected to be treated as the normal control group. The rats in each administration group were given corresponding liquid intragastrically， and the normal control group and model control group were given equal volumes of normal saline intragastrically， once a day， for 28 consecutive days. After the last administration， the levels of serum creatinine （SCr）， blood urea nitrogen （BUN）， malondialdehyde （MDA）， superoxide dismutase （SOD）， glutathione peroxidase （GSH-Px） and 24 h urinary protein （UP） were detected； the renal index was calculated； the pathological changes of renal tissue were observed and the pathological score was calculated； the apoptotic rate of cells in renal tissue and the expression levels of Caspase-3 and Bcl-2 associated X protein （Bax）， as well as the phosphorylation levels of silent information regulator of transcription 1 （SIRT1） and AMP-activated protein kinase （AMPK） were detected. RESULTS Compared with the model control group， the levels of SCr， BUN， UP and MDA， the renal index， the pathological score of renal tissue， the apoptotic rate of cells in renal tissue， the protein expression levels of Caspase-3 and Bax in renal tissue of rats in each administration group were decreased significantly； SOD and GSH-Px levels， phosphorylation levels of SIRT1 and AMPK protein were increased significantly （P＜0.05）， and the effect of proanthocyanidins was in a dose-dependent manner （P＜0.05）. There were no significant differences in the above indexes between proanthocyanidins 200 mg/kg group and benazepril hydrochloride 5 mg/kg group （P＞0.05）. CONCLUSIONS The improvement effect of proanthocyanidins on AKI rats may be related to the activation of SIRT1/AMPK signaling pathway to inhibit oxidative stress.