Abstract: Objective To study the value of erythrocyte sedimentation rate (ESR) combined C reactive protein (CRP) in the diagnosis of subacutethyroiditis (SAT). Methods Two hundred and fourteen cases of SAT from January,2011 to December,2015,and 288 cases of Graves disease in the same period were selected.The thyroid related indicators (FT3,FT4,TSH,TRAb,TPOAb and Iodine uptake rate),CRP and ESR levels were detected and statistical compared.The ROC curve of CRP,ESR and CRP combined ESR on diagnosis of subacute thyroiditis were made,and the sensitivity,specificity,and area under curve (AUC) were compared. Results The FT3 and FT4 levels of the observation group were significantly higher than those of the control group,the difference was statistically significant (P<0.05).The TSH,TPOAb and Iodine uptake rate of the observation group were significantly lower than those of the control group,the difference was statistically significant (P<0.05).The CRP and ESR levels of the observation group were significantly higher than those of the control group,the difference was statistically significant (P<0.05).The sensitivity of CRP combined ESR on the diagnosis of SAT was 96.7%,which was higher than that of CRP (92.5%) and ESR (86.5%),but the difference was not statistically significant (P>0.05).The AUC of CRP combined ESR on the diagnosis of SAT was 0.804,which was higher than that of CRP (0.755) and ESR (0.804). Conclusion Erythrocyte sedimentation rate combined C reactive protein could be used as the effective diagnosis indicators of subacutethyroiditis,and the effect was better than only erythrocyte sedimentation rate or C reactive protein.