To investigate the relationship between the changes of Lewis(y) antigenic content and the drug resistance of the cells to carboplatin in ovarian cancer lines with RMG-Ⅰ-H which expresseed higher Lewis(y) antigen on cell surface stably. RMG-Ⅰ was one kind of epithelial ovarian cancer cell lines. Cell lines RMG-Ⅰ-C and RMG-Ⅰ-H were obtained from RMG-Ⅰ which were transfected with keno-plasmid and α1, 2-fucosyltransferase gene, respectively. The method of methyl thiazolyl tetrazolium (MTT) was used to determine the fractional inhibition ratio (IR) of the three cell lines which were affected by carboplatin in different concentrations. Accordingly, the IC₅₀ of the three cell lines could be calculated. Carboplatin induced apoptosis of three cell lines was observed by flow cytometry (FCM). In addition, the apoptotic ratios of the three lines that were treated by 30 mg/L and 60 mg/L carboplatin were measured by the FCM at the same time. And then, the apoptosis conditions of the three lines were observed by the methods of fluorescent staining and transmission electron microscope (TEM). The IC₅₀ of RMG-Ⅰ-H was (58.07±2.42), which was obviously higher than that of RMG-Ⅰ(28.83±3.57) and RMG-Ⅰ-C(25.71±8.24), all showed a significant statistical difference (P < 0.01) and there was no statistical difference between the latter two ones(P > 0.05). FCM analysis confirmed the cell apoptosis in the three lines. The corr-apoptotic ratios of RMG-Ⅰ-H treated with 30 mg/L and 60 mg/L carboplatin were (20.43±0.71)% and (38.11±0.33)%, respectively, which were about 49%～63% of the RMG-Ⅰ(35.87±3.84)%, (63.37±9.59)% and RMG-Ⅰ-C(34.80±3.59)%, (60.17±6.64)%, both presented a statistical difference (P < 0.05). But there was no significant statistical difference between the latter two ones (P > 0.05). The apoptotic degree of RMG-Ⅰ-H was lower than that of the other cell lines in the same carboplatin concentration with the method of inv-fluorescence microscopy and transmission electron microscopy (TEM). The drug resistance of ovarian cancer cells to carboplatin was stronger when the Lewis(y) antigenic contents on cell surface increased.