Aim To investigate effects of constant magnetic field(CMF) on nitric oxide(NO) production and nitric oxide synthase(NOS) activity in human umbilical vein endothelial cells(hUVEC) intervened by advanced glycosylation endproduct(AGE).Methods The third passage of cultured hUVEC were used.AGE modified bovine serum albumin(AGE-BSA) was prepared by sugar incubation.The cells were divided into six groups: control group,AGE group(AGE-BSA 100 μg/L),AGE-BSA with 1×10~(-4)T,5×10~(-4)T,10×10~(-4)T and 20×10~(-4)T of cons tant magnetic field group.Samples were collected 24 h later.NO levels in the supernatant were determined using Griess reagent,and NOS activity of hUVEC was dedected.Results NO levels and NOS activity significantly decreased in AGE-BSA group(p<0.05). In 1×10~(-4)T,5×10~(-4)T,10×10~(-4)T and 20×10~(-4) T groups,NO levels and NOS activity significantly increased compared with AGEBSA group(p<0.05).Conclusion AGE-BSA can inhibit NO production and NOS activity in hUVEC,whereas 1×10~(-4)T to 20×10~(-4)T of constant magnetic field can intensity-dependently antagonize the effects of AGE-BSA on NO production.