Objective To study the relationship between urinary ceruloplasmin(CP)and diabetic nephropathy. Methods Two hundred and thirty-six patients with type 2 diabetes mellitus were divided into normal albuminuria group(DMN group, 129 cases) and micro-albuminuria group ( DMMA group, 107 cases).Eighty-one healthy people were admitted into control group. The levels of urinary CP, serum CP, urinary albumin(Alb)and urinary creatinine(Cr)were measured. Results The median of urinary CP/Cr in DMMA group (2.55 ng/mmol) and DMN group (1.18 ng/mmol )was higher than that in control group(0.92 ng/mmol )(P<0.01 ). There was no significant difference in the levels of serum CP in each group (P>0.05 ).The urinary Alb/Cr was significantly positively correlated with urinary CP/Cr (r=0.188 ,P<0.01 )in patients with type 2 diabetes mellitus. The course of diabetes mellitus was a risk factor of urinary CP/Cr and Alb/Cr increase. Conclusions The urinary CP shows increasing tendency in accord with urinary Alb in type 2 diabetes mellitus patients. Urinary CP elevates obviously and correlates with diabetic nephropathy. Urinary CP may be used to monitor the onset, progress and therapeutic effect of diabetic nephropathy.