Aim To investigate the regulation of X-box binding protein-1 (XBP-1) and acyl-CoA cholesterol acyltransferase-2 (ACAT-2) expression by cholesterol in hepatic cell and enterocyte. Methods HepG2 cell and Caco2 cell were incubated with different concentration of free cholesterol and oxidative cholesterol. The mRNA level of XBP-1 and ACAT-2 in cells were detected by semi-quantitative RT-PCR. Results In cells incubated with free cholesterol and oxidative cholesterol, XBP-1 and ACAT-2 mRNA levels in HepG2 cell and Caco2 cell were up-regulated, and were dependent on the concentration increase. Conclusions Both of cholesterol and oxidative cholesterol can induce UPR, and ACAT-2 mRNA level can be up-regulated, the results imply the possibility that ACAT-2 may be regulated by UPR; in view of ACAT-2 playing an important role in the cholesterol esterification and absorption, UPR may have important significance in cholesterol absorption.