Objective：To investigate effect of FK506 on d-BSA-induced proliferation of NRK-52E cells. Methods：Different concentrations of FK506 on d-BSA-induced NRK-52E cells, the cells were observed at different times within proliferation.Proliferation was determined by MTT assay. Results：①While l mg/ml d-BSA did not have any significant difference on NRK-52E proliferation that was not related with time(P>0.05);5,10,20,50mg/ml d-BSA could induce proliferation of NRK-52E for 6 hours(P<0.05).②0.1ng/ml FK506 pretreatment with NRK-52E for 4 hours did have no significance on d-BSA-induced proliferation of NRK-52E cells(P>0.05);1,10,20ng/ml FK506 commonly incubated for 6 hours with d-BSA after pretreatment for 4 hours,proliferation was inhibited in a dose- and time- dependent manner(P<0.05). Conclusion：D-BSA may induce proliferation in NRK-52E that FK506 could inhibit.