Abstract Objective: To discuss the value of CT in the diagnosis of costal tumor or tumorlike lesions. Materials and Methods: All the patients took the examination of CT, two of them took MRI. Results: Thirty-two cases belong to benign lesions, 12 cases of them are bone island, 9 cases are fibrous dysplasia, 7 cases are chondrogenous tumor, 4 cases are infective lesions. Eighteen cases are malignant lesions, 10 cases of them are metastatic tumor, 4 cases are myeloma, 4 cases are giant cell tumor of bone. Conclusion: There are some characteristic CT findings which are helpful to diagnose a certain tumor. We can distinguish benign tumor from malignant tumor of rib in the majority of cases by these characterstics.