Abstract： Objective To investigate the diagnostic efficacy of combined blood and urine biochemical tests in the early biochemical testing of diabetic nephropathy.Methods A total of 451 patients with diabetic nephropathy(obser-vation group)and 472 patients with simple type 2 diabetes mellitus(control group)admitted to the Hechi People's Hospital from January 2022 to June 2023 were randomly selected as the study objects.Both groups of patients re-ceived blood and urine biochemical tests,and the test results were compared.Results The biochemical indexes of blood and urine in the observation group were higher than those in the control group,and the differences were statisti-cally significant(both P<0.05).In the early diagnosis of diabetic nephropathy,the diagnostic efficiency of blood com-bined with urine biochemical test was higher(area under curve was 0.980,95%CI:0.969-0.988,sensitivity was 91.80%,specificity was 98.52%).Conclusion The diagnostic value of blood combined with urine biochemical tests in the early biochemical testing of diabetic nephropathy is high.