Abstract: Flow cytometry (FCM) has been more and more widely applied in the researches of cutaneous T-cell lymphoma for its capability to rapidly and simultaneously analyze properties of multiple cells in a quantitative manner. Since FCM could detect abnormal immunophenotypes and monoclonality of neoplastic T cells using antibodies to T-cell superficial antigens and T-cell receptor beta-chain variable region families (TCR-V β), respectively, it has become an important tool for ancillary diagnosis and monitoring of