Aim To investigate whether overexpression adipophilin induces acyl-coenzyme A∶cholesterol acyltransferase 1 (ACAT1) high expression and lipid accumulation in THP-1 macrophages. Methods The THP-1 cells were differentiated to macrophages through incubation with 160 nmol/L phorbol 12-myristate 13-acetate (PMA) for 24 h. To make overexpressed adipophilin macrophages, the pcDNA3.1-HA-adi constructed was transfected to THP-1 macrophages. Then, cells were incubated with or without oxidized low density lipoprotein (ox-LDL) and/or S-58035 for different time. ACAT1 and adipophilin expression were investigated with reverse transcription polymerase chain reaction (RT-PCR) and Western blot. Oil red O staining and high perfomance liquid chromatography (HPLC) were used to analyze the cellular cholesteryl ester accumulation. Results With the increasing incubated concentration of ox-LDL, both adipophilin and ACAT1 mRNA up-regulated obviously. The upregulated expression of ACAT1 induced by ox-LDL was inhibited by S-58035, and intracellular lipid droplets also decreased. Compared with control, transfecting pcDNA3.1-HA-adi increased adipophilin protein level in THP-1 macrophages. Overexpression adipophilin cells significantly upregulated ACAT1 expression and promoted intracellular lipid accumulation. Ox-LDL synergized the effect of ACAT1 high expression. But the effect could be inhibited by S-58035. Conclusion Overexpression adipophilin can upregulate the ACAT1 expression in THP-1 macrophages, and increase cellular cholesteryl ester. It suggested that adipophilin accumulated cellular cholesteryl ester by ACAT1 in THP-1 macrophages.