Atherosclerosis is an inflammatory disease. There are many immune cells filled in atherosclerotic lesions, particularly in unstable plaques. The understanding on the recruitment, differentiation and activation of immune cells in atherosclerosis have been expanded in recent years. Epidemiological surveys show many associated viral and bacterial infections. Preliminary studies have identified several autoantigens and raised the "autoimmune hypothesis". Based on this novel viewpoint, the immunomodulation and immunization have been taken as the new strategies for prevention and treatment of atherosclerosis. This will markedly improve our research level and identify new therapeutic targets in atherosclerosis.