In order to investigate the differences in Cd tolerance between purple leaf rape(PR)and green leaf rape(GR)under Cd stress conditions，a hydroponic experiment was conducted using 19-Z10-P PR and 19-Z10-G GR as test materials. Two Cd concentrations，0 mg·L-1(control)and 30 mg·L-1(treatment)，were set up to analyze the plant height(Ph)，root length(Rl)，shoot fresh weight(Sfw)，root fresh weight(Rfw)，shoot dry weight(Sdw)，root dry weight(Rdw)，chlorophyll(Chl)，anthocyanin(Ant)，relative water content(Rwc)，relative electrical conductivity(Rec)，malondialdehyde(MDA)，proline(Pro)，hydrogen peroxide(H2O₂)，soluble sugar(Ss)，superoxide dismutase(SOD)，peroxidase(POD)，catalase(CAT)，Cd content，single plant extraction amount(Ea)，cadmium tolerance coefficient(TI)，and transport coefficient(TF)of rapes after Cd stress，and the differences in Cd tolerance between two rape varieties were studied. The results showed that:(1)Compared with CK，after treated with Cd stress，the pH，RL，Sfw，Rfw，Sdw，Rdw，Rwc，Chl，Ant content and CAT activity of PR and GR were decreased，while the Rec，MDA，Pro，H2O₂，Ss content and SOD，POD activity were increased. Among the above indicators，the Ph，Sfw，Chla，Rwc，and Rec of GR and PR had similar variations，while the Chlb，Chla+b and Ant variations showed as GRPR；(2)The difference in the ability of PR and GR to absorb and transport Cd was not significant，and the differences of the shoot Cd content，root Cd content，single plant extraction amount，and the translocation factor of Cd were not significant，TI showed as PR(-0.44)>GR(-0.58)；(3)The comprehensive evaluation score of the membership function method showed as PR(0.50)>GR(0.41). So，after Cd stress，the growth of PR and GR was inhibited，the content of photosynthetic pigments and anthocyanins decreased，leaves lost water and turned yellow，reactive oxygen species increased，membrane damage occurred，and osmotic regulatory substances increased. The Cd tolerance index and comprehensive Cd tolerance ability of PR were higher than those of GR.