Objective:To investigate the positive expression rate of bcr/abl fusion gene in chronic myelogenous leukemia (CML) and its clinical significance. Methods: The RT-PCR technique was used to detect the bcr/abl gene in CML. Results: Out of 9 cases of chronic phase of CML, 8 showed positive expression of bcr/abl gene which accounted for 88. 9% . Conclusions: Bcr/abl gene detecting technique has significance in clinical classification of CML. When bcr/abl gene expresses positively, it contributes to differential diagnosis in blast crisis of CML and acute myelogenous leukemia ( AML) at the first diagnosis.