Chronic myeloid leukemia (CML) is caused by BCR/ABL,resulting from reciprocal translocation between chromosomes 9 and 22,t (9;22)(q34;q11).1 BCR/ABL is a specific marker of the disease sharing a high tyrosine kinase activity,thus has become an attractive molecular target for therapeutic intervention of CML.2,3 Traditional methods for detecting BCR/ABL including FISH and western blotting require multiple steps and are time-consuming.In this work,one-step reverse transcriptase polymerase chain reaction (RT-PCR) coupled with microchip capillary electrophoresis (MCE) was established to analyze BCR/ABL fusion gene.The use of one-step multiplex RT-PCR can simplify the RT-PCR procedure and thus reduced the risk of sample wastage and contamination.RT-PCR combined MCE also enhanced the sensitivity for amplified target DNA and dramatically shorted the analysis time.Moreover,this assay can simultaneously identify both b3a2,and b2a2.Orthogonal array design was used to optimize the reaction system in the work,which can be investigated mutual effects of PCR parameters simultaneously with reliability.Under the optimal conditions,the results indicated that this approach is high effective,reproducible and sensitive,and would be suitable for determination of BCR/ABL in clinic diagnose.