Objective To compare the effects of different dialysis modes, high-flux hemodialysis, on-line hemdiafiltration and low-flux hemodialysis on serum β2- microglobulin. Methods Seventy chronic dialysis patients were randomized to receire low-flux hemodialysis (HD n=28), high-flux hemodialysis (HFHD n=20) and on-line hemodia filtration(HDF n=22).The serum blood urea nitrogen, creatinine, phosphorus and β2- microglobulin were examined pre and post dialysis. Results In the HDF group, the reduction ratio of serum blood urea nitrogen, creatinine and phosphorus was higher than that in the other groups. The concentration of β2-microglobulin significantly reduced after the dialysis session in the HFHD group and the HDF group while no significance was found in the HD group. Conclusion HFHD and HDF could efficiently eliminate both the low molecular weight solutes and β2- microglobulin. HFHD and HDF should be applied to remove the β2-microglobulin in the maintenance hemodialysis patients.