Virus-specific neutralizing antibodies are key in creating an immune protection against viral infections. NAbs have been widely used in the past as a passive antibody therapy for SARS-CoV and Ebola virus. They are also used in evaluating the efficacy of vaccines against smallpox, polio and influenza viruses. In this study plasma samples from 175 adult COVID-19 patients admitted to Shanghai Public Health Clinical Center were collected and then screened using a sensitive pseudotyped-lentiviral-vector-based neutralization assay. All COVID-19 patients that participated in this study had mild to common symptoms and developed peak NAbs levels 10-15 days after the onset of the disease. A wide variability in NAbs plasma levels was observed among patients.