Abstract: Objective: To establish a modified reverse-banding R-banding technique for identifying caryotgper of chromosome.Methods: Thirty patients with malignant hemopathy were detected using modified technique of R-banding,and the caryotype of the cases was studied.Acridine orange solution was substituted with 10% Giemsa,the composition of the reagents was readjusted and the procedures of the experiment were simplified.Results: In the 30 patients of malignant hemopathy,29 cases presented abnormal caryotype.Ph¹ was observed in all 11 cases of chronic myelocytic leukemia(CML) and 3 of the 7 cases of acute lymphoblastic leukemia(ALL);chimera was found in 1 of the 7 ALL cases and 4 cases demonstrated-22,+Mar(D?),del(11) (q23) and normal karyotyp or multiploid.Among the 10 cases of acute myeloid leukaemia(AML),2 of the 3 cases of M2 were t(8;21),1 case appeared 15q⁺;3 of the 5 cases of M3 were t(15;17),1 case was M5,1 case was rare caryotype,1 case was M2,2 cases showed abnormal number on myelodysplastic syndrome(MDS) (-21,+16) and 1 case appeared small Mar.No characteristic chromatosome abnormality was found.Conclusions: A relatively stable and accurate chromosome banding image can be obtained by using modified R-banding technique and the identification of chromatosome caryotype becomes easier to handle and recognize.This technique is recommended for wide use in the laboratory.