Objective To analyze the serum antibody IgM and IgG levels of patients with coronavirus disease 2019 (COVID-19), and provide basis for clinical diagnosis and treatment. Methods Chemiluminescence method was used to quantitatively detect the serum antibody levels of hospitalized patients diagnosed with COVID-19 between February 27 and March 5, 2020. Difference in antibody detection positive rates and antibody levels in patients in different disease course (< 7, 7-14, >14 days), different gender and age group (< 18, 18-, 41-, >65 years old) were statistically analyzed. Results Among 550 patients with confirmed COVID-19, 253 were males and 297 were females, with a median age of 61 (50, 69) years. The overall positive rate of IgM and/or IgG antibody was 92.00%, overall positive rates of IgG and IgM were 91.45% and 76.18% respectively. Positive rate of IgM or IgG increased gradually with the progress of the disease, positive rate increased from 31.25% in the early stage to 94.82%. Positive rate of IgG antibody was higher than that of IgM antibody when disease course was more than 14 days (χ²=49.697, P < 0.001). Difference in antibody positive rate among different age groups was statistically significant (χ²=15.339, P=0.002), positive rate was higher in 41- and >65 years old group; there was no significant difference in antibody positive rate between different gender groups (χ²=0.006, P=0.094). IgM was produced within 1-2 weeks after disease onset, reached the peak within 2-3 weeks, and gradually decreased to the normal level after 4 weeks; IgG began to produce at about 1st week after disease onset, reached the peak at about the 3rd week, and still remained stable at 50th days. There was no significant difference in the levels of IgM and IgG among different age groups and gender groups (all P>0.05). Conclusion Positive rate of IgM or IgG in the early stage of disease is relatively low, which increases with the disease process, but antibody level does not show the difference in age and gender, antibody detection can assist diagnosis of COVID-19 patients.