Abstract： Objective The UAER (urinary albumin ejection rate,mg/24h) andlevels of urinary IgG4(μg/24h)were detected,IgG4/AER index was counted in 70 Type 2 diabetics and 18 healthy individuals.Methods 70 patients were devided into three groups.The UAER was lower than 30mg/24h in group NDN (25 patients),30-300mg /24h in group EDN (27 patients) and higher than 300mg/24h in group CDN(18 patients).Results The levels of urinary IgG4 was higher significantly in group CDN (338.4+228.5ug/24h) and in group EDN(96.0+81.7ug/24h)compared to group NDN (9.9+6.3ug/24h) and healthy subjects (9.8+4.4ug/24h),p<0.01.IgG4/AER index was lower significantly in group CDN(0.31+0.28) compared separately to group EDN(0.87+0.63),group NDN(0.68+0.40) and healthy subjects (0.66+0.33),p<0.05.The association between the UAER and urinary IgG4 values was studied separately in three group patients by linear relation analysis.The both were correlated significantly in group NDN(r=0.6153,p<0.001) and group EDN(r=0.7550,p<0.001),and not correlated in group CDN(r=0.1615,p>0.05).Conclutions levels of urinary IgG4 was increased significantly in early stage of diabetic nephropathy and correlated with UAER,and IgG4/AER index decreased that might be the development of diabetic nephropathy.