The serious risk of atrial fibrillation (AF) is stroke and other thromboembolic events caused by local thrombosis that sheds off and travels in blood circulation to blood vessels throughout the body. Platelet activation is an important part of the mechanism of thrombosis, where mean platelet volume (MPV) serves as one of the markers of platelet activity. Its testing is simpler, more economical, more widely available, and more convenient than others. A number of studies at home and abroad have shown that MPV is related to AF itself, the occurrence of AF, and the risk of AF-related stroke. This review aimed to provide a more complete theoretical basis for the prevention of AF-related stroke.