Abstract: Objective:To explore the reason of misdiagnosis of acute lymphatic leukemia as rheumatic diseases and reduce the misdiagnosis.Methods:Analyse the clinical manifestation and laboratory findings of 7 cases in acute lymphatic leukemia transfer from department of rheumatology.Results:The primary symptoms of 7 patients infected with acute lymphatic leukemia were musculoskeletal pain.Then the diagnosis was made from 1 month to 12 months after symptom occurring.The seven misdiagnosis patients included:seronegative spondylarthritis 4 cases,connective tissue disease 1 case,juvenile spondylarthritis 1 case,and rheumatoid arthritis 1 case.Conclusions:To reduce the misdiagnosis,a bone-marrow examination should be done before steroid treatment for the patients with musculoskeletal pain.