Platelets are the blood cells in the body responsible for hemostasis and are derived from the proliferation and division of megakaryocytes in the bone marrow. The role of platelets is as follows: First, adhesion, that is, platelets have the ability to adhere to the surface of other substances, platelets can adhere to the endothelial cells of blood vessels, thus playing a hemostatic role. Second, the role of aggregation, that is, platelets have the ability to gather together to form a platelet clot, which is conducive to the role of platelets to stop bleeding. Third, the role of release, platelets can also release a variety of pro-coagulant substances to promote blood clotting, thereby playing a hemostatic role. Fourth, the role of contraction, when the formation of blood clots will be further contraction of platelets, resulting in blood clots more tightly blocked in the bleeding site, to further play the role of hemostasis. Through the above roles, platelets play an important role in the body’s hemostatic function, and the body is prone to bleeding when the number of platelets is reduced.