Provided are a composition for diagnosing vascular disease including an agent measuring a level of interleukin 12 receptor β2 protein in the blood, and a kit for diagnosing vascular disease including the same. Further, provided is a method for diagnosing vascular disease, the method including the step of measuring a level of interleukin 12 receptor β2 protein in a blood sample separated from an individual suspected of having vascular disease. Furthermore, provided are a composition for preventing or treating vascular disease including an interleukin 12 receptor β2 activity inhibitor, and a method of screening a therapeutic agent for vascular disease, the method including the step of treating smooth muscle cells with a test agent for vascular disease treatment and measuring an expression level of interleukin 12 receptor β2.