Abstract: Karyotypic analysis of the peripheral blood cell in 32 patients with cutaneous T cell lymphoma (CTCL) was studied. Among them,there were mycosis fungoides (MF) 23 cases,non epidermotropic cutaneous T cell lymphoma (NCTCL) 8 cases, Sézary syndrome (SS) 1 case. 26 cases had abnormal karyotypes including structural and quantitative aberration. Chromosome deletion and aneuploidy were found mainly. There was no relationship between the aberration and the type of CTGL,duration of the disease and the size of lesions. But aberration rate in MF tumor stage waa higher than in pre-tumor stage. It suggests chromosome aberration may be related to the severity and prognosis of CTCL.