Antiphospholipid syndrome (APS) is a systemic autoimmune disease with the appearance of anti-phospholipid antibody (ACLA), Anti β2GPI and lupus anticoagulant (LAC) in serum. The antigen-antibody reaction on cell surface leads to thrombosis, miscarriage and inflammation. Clinical findings are diverse and include thrombosis in veins and arteries, pregnancy loss, thrombocytopenia, neurological and cardiac manifestation. In recent years the mechanism and pathophysiology of antiphospholipid damages has disclosed new insight to this syndrome, and better understanding and interpretation of criteria laboratory tests.