Signal transducer and activator of transcription 4 （STAT4） is one of the signal transducer and activator of transcription （STAT） protein family which share common structural features. As an intracellular signal transducer,STAT4 involves in cellular differentiation,inflammation and other physiological or pathological process. Some recent studies suggest that STAT4 influence innate and adaptive immunity as well as the distribution of arterial smooth muscle cells in the process of atherogenesis. Therefore,extensive researches are necessary in revealing underlying mechanisms of STAT4’s role in the process of atherogenesis.