Abstract: Objective:To compare the clinical efficacy of hemoperfusion at early or late stage during the hemodialysis combined with hemoperfusion treatment.Methods:A total of 106 uremia patients who were treated by combination of hemodialysis and hemoperfusion were included and randomly divided into group A and group B(53 cases each group).Blood perfusion was added 2 hours before dialysis in group A, while blood perfusion was added at last 2 hours of dialysis in group B.Three months after treatment, the levels of parathormone(PTH),blood urea nitrogen(BUN),creatinine(Cr),β₂-microglobulin (β₂-MG) between two groups were compared.The changes of the sleep situation,blood pressure,appetite,skin itching,body pain,numbness and restless leg syndrome before and after treatment were also observed.Results:The levels of BUN,PTH, Cr and β2-MG in two groups significantly decreased after treatment(P<0.05 to P<0.01),while the decreasing degree of these indexes in group B was more than that in group A(P<0.01).After treatment, the sleep disorder, high blood pressure and toe pain in two groups significantly improved(P<0.05 to P<0.01),while the poor appetite in two groups did not improve significantly(P>0.05).The sensory disorder and numbness improved only in group B(P<0.01).Conclusions:The combination of hemoperfusion at late stage of dialysis can significantly increase the clear rate of serum harmful substance, and improve the sensory disorder and numbness symptom.