Bone aspiration is also called bone marrow aspiration, and its main function is to diagnose hematologic diseases. 1.In clinical cases where abnormalities in the size, shape and number of blood cells are found after routine blood tests, but the specific cause cannot be determined after judgment, bone marrow aspiration and blood smear examination are needed to make further judgment based on the results, such as complete blood cytopenia, erythrocytosis, etc. 2.After a long period of Fever, after examination can not determine the specific diagnosis, need to do bone marrow aspiration to find parasites, or bone marrow aspiration after bacterial culture, or bone marrow aspiration after smear examination to exclude the possibility of leukemia. 3, clinical suspicion of blood system diseases, but can not confirm the diagnosis, need to do bone marrow aspiration after further confirmation of the diagnosis.