Background: Serology tests for detecting the antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can identify previous infections and help to confirm the presence of current infection. Objective: The aim of this study was to evaluate the performances of a newly developed high throughput immunoassay for anti-SARS-CoV-2 IgG antibody detection. Results: Clinical agreement studies were performed in 107 COVID-19 patient serum samples and 226 negative donor serum/plasma samples. Positive percent agreement (PPA) was 46.15 % (95 % CI: 19.22 % ~74.87 %), 61.54 % (95 % CI: 31.58 % ~86.14 %), and 97.53 % (95 % CI: 91.36 % ~99.70 %) for samples collected on 0− 7 days, 8− 14 days, and ≥15 days from symptom onset, respectively. Negative Percent Agreement (NPA) was 98.23 % (95 % CI: 95.53 % ~99.52 %). No cross-reactivity was observed to patient samples positive for IgG antibodies against the following pathogens: HIV, HAV, HBV, RSV, CMV, EBV, Rubella, Influenza A, and Influenza B. Hemoglobin (200 mg/dL), bilirubin (2 mg/dL) and EDTA (10 mM) showed no significant interfering effect on this assay. Conclusion: An anti-SARS-CoV-2 IgG antibody assay with high sensitivity and specificity has been developed. With the high throughput, this assay will speed up anti-SARS-CoV-2 IgG testing.