·AIM:To study the effect of urotensin Ⅱ(U-Ⅱ),a new biological activity substance,on proliferation of lens epithelial cell(LEC).·METHODS:Different concentrations of U-Ⅱ were incubated with in vitro cultured LEC in vitro.The activities of LEC were detected via methyl thiazolyl tetrazolium(MTT).The proliferations of LEC were detected via 3H-TdR.·RESULTS:The absorbences of groups 10-9mol/L U-Ⅱ,10-8mol/L U-Ⅱ,10-7mol/L U-Ⅱ and 10-6mol/L U-Ⅱ were higher than that in control group(P<0.05,P<0.05,P<0.01,P<0.01);the radio-activities of 3H-TdR in groups 10-10mol/L,10-9mol/L U-Ⅱ,10-8mol/L U-Ⅱ,10-7mol/L U-Ⅱ and 10-6mol/L U-Ⅱ were higher than that in control group(P<0.01),which were 1.36,1.40,1.45,1.59 and 1.66 times respectively,with a dose-dependent manner.·CONCLUSION:U-Ⅱ can induce proliferation of LEC.·