Objective To explore the effect of acupuncture on the endoplasmic reticulum stress IRE l-CHOP signal pathway and the expression levels of related apoptosis genes in pancreatic tissue of rats with STZ-induced diabetes mellitus. Methods Eighty SD rats were selected, among which, 10 were fed with normal diet and taken as blank control group ("blank group" for short), the other 70 rats were fed with high fat and high glucose food and injected with small dosage of STZ intraperitoneally, and 30 models were established successfully. The models were randomly divided into acupuncture treatment group (~'acupuncture group" for short), model control group ("model group" for short) and western medicine group (metformin) with 10 rats in each group. After treatment for 4 weeks, RBG, and the expression levels of CHOP, IRE 2, Bax, Bcl-2 protein and mRNA in pancreatic tissue of rats were determined. Result Compared with the conditions before treatment, RBG reduced obviously in the acupuncture group and western medicine group (P〈0.05), and there was no statistical difference in RBG in the model group and blank group (P〉0.05); the expression levels of CHOP, IRE 1 and Bax proteins in pancreatic tissue of rats in the model group were significantly higher than those in the blank group (P〈0.05), the expression results in the acupuncture group and western medicine group were significantly lower than those in model group (P〈0.05); the expression levels of CHOP, IRE 1 and Bax mRNAs in pancreatic tissue of rats in the model group were significantly higher than those in the blank group (P〈0.01), the expression results in the acupuncture group and western medicine group were significantly lower than those in the model group (P〈0.01); the expression level of Bcl-2 protein in the model group was significantly lower than that in the blank group (P〈0.05), the expression results in the acupuncture group and western medicine group were significantly higher than that in the model