Abstract：Objective To explore the clinical value of combined detection of serum cystatin C and urinary microprotein in the diagnosis of early renal dysfunction. Methods A total of 152 patients with suspected early renal impairment who were diagnosed and treated in our hospital from October 2019 to October 2021 were selected and divided into study group 1 （62 cases of hypertension）, study group 2 （58 cases of diabetes mellitus） , and study group 3 （32 cases of systemic lupus erythematosus）according to different primary diseases. 55 subjects who underwent physical examination in our hospital during the same time period were selected and included in the control group. Serum cystatin C and urinary microprotein levels were measured in four groups, and receiver operating characteristic （ROC） curve was used to analyze the clinical value of the two indicators alone and in combination in the diagnosis of early renal impairment. Results The detection levels of serum cystatin C and urine microprotein in study group 1, 2 and 3 were higher than those in the control group, with statistically significant differences between the groups （F＝501.110, 368.190, all P＜0.05）;the positive detection rates of serum cystatin C and urinary microprotein in study group 1, 2 and 3 were higher than those in the control group,with statistically significant differences between the groups （χ2＝77.455, 73.569, 63.735, 83.032, 76.307, 70.964, all P＜0.05）; the differences in the positive detection results of serum cystatin C and urine microprotein in the study group were not statistically significant when compared with the combined test （χ2＝1.485, 0.227, all P＞0.05）. The sensitivity and specificity of the combined test were higher than those of the single test for both indicator. Conclusion The combination of indicators has high specificity and sensitivity in the diagnosis of early renal damage, and has important clinical diagnostic value.