Objective To investigate the effects on proliferation of multiple myeloma cell lines U266 and RPMI 8226 induced by puerariae radix flavones (PRF) in vitro and its possible mechanism.Methods Exposed to 0,10,30,50,100 μg/ml PRF for 48 h and 72 h,the U266 and RPMI 8226 cells proliferation inhibitory rates were detected by MTT assay,cell cycles by flow cytometry (FCM),morphologic changes of U266 cells by Wright' s staining,and early-stage apoptotic rates of U266 cells by FITC-Annexin V/PI staining with FCM.Analysis of DNA fragment was made to test characteristic apoptosis DNA ladder in U266 cells.Results 0,10,30,50,100 μg/ml PRF could inhibit the proliferation of U266 and RPMI 8226 cells in a dose-dependent manner (U266 ＞ RPMI 8226).Cell cycle analyses in U266 and RPMI 8226 cells showed that sub-diploid peaks,but cell cycles changed minor.Wright's staining of U266 cells showed hardly any apoptostic character istic.Annexin V/PI double staining indicated that early-stage apoptotic rates of U266 cells exposed to 0,10,30,50,100 μg/ml PRF for 48 h were mildly increased in a dose-dependent manner.They were (3.20±0.36) ％,(5.20±0.92) ％,(7.30±1.22) ％,(8.10±0.53) ％ and (10.80±0.90) ％,respectively.The group differences had statistical significance (P ＜ 0.05).Analysis of DNA fragment barely exhibited the characteristic DNA ladder in U266 cells.Conclusion A certain concentrations of PRF could inhibit the proliferation of U266 and RPMI 8226 cells significantly.It is suggested that apoptosis related to the proliferative inhibition mechanism induced by PRF in U266 cell line,but not main.Other pathways such as necrosis and autophagy whether or not involved need further investigation.