Aim To determine the effect of interplay between endoplasmic reticulum stress (ERS) and autophagy on vascular calcification (VC). Methods VC model in rats was induced by vitamin D3 plus nicotine. The deposition of calcium in aorta was determined by alizarin red staining and assessment of calcium content. The protein levels in aorta were measured by Western blot. Results Compared with control group, deposition of calcium in aorta was increased in VC group. The protein levels of SM-22α and calponin in calcified vessels were decreased, whereas that of bone morphogenetic protein 2 (BMP-2) and RUNX2 was increased. ERS and autophagy was activated in calcified aorta, shown by increased levels of glucose regulated protein (GRP78), C/EBP homogous protein (CHOP), LC3Ⅱ and Beclin-1. Tunicamycin (10 μg/kg per day), an ERS inducer exacerbated VC and transdifferation of vascular smooth muscle cells from contracted-like to osteoblasts-like phenotype. It also promoted ERS and auphagy. 3-methyladenine (10 mg/kg per day), an autophagy inhibitor prevented stimulation of autophagy, but promoted ERS activation in calcified aorta, while it also exaggerated VC and transdifferation of vascular smooth muscle cells. Conclusion The interplay between ERS and autophagy plays an important role in progression of VC.