Objective:To observe the effects of Qingdupian on the u-PA expression in HL-60 cells.Methods: 2 mL of Qingdupian was diluted with RPMI-1640 culture medium supplemented with 10% fetal bovine serum to 12 diluted liquids from 1:10 to 1∶(1 600) concentrations. Ara-c was used as the positive control

and the culture medium as the negative control.MTT assay was performed.The supernatant was collected for ELISA essay to determine the activity of u-PA.Results: The results research showed that Qingdupian fluid has inhibiting effects on HL-60 cells.And the u-PA activity in the supernatant fluid dropped with the raise of medicine concentration.Conclusions: It suggests that the curative effect of Qingdupian is related to its effect of declining u-PA activity on leukemia cells.