Objective：To retrospectively analyze the changes of related laboratory indexes at first admission in patients with coronavirus disease 2019（COVID-19），so as to provide laboratory reference for early clinical diagnosis and treatment. Methods：The laboratory examination indexes，including blood routine，biochemical indexes，inflammatory markers，coagulation function，and lymphocyte subsets count were selected and analyzed at first admission in 91 patients with COVID-19 and admitted to Nanjing Public Health Medical Center. Results：The total white blood cells and the lymphocytes counts in the routine blood examination were decreased in 21.98% and 17.58% of patients，respectively. In biochemical indexes，ALT，AST，and LDH were elevated in 13.19%，14.29%，and 36.67% of patients，respectively； the proportions of patients with elevated phosphocreatine kinase in myocardial enzyme examination were 18.37% in male and 9.75% in female，and creatine kinase isoenzyme，myoglobin，and troponin I were elevated in 5.68%，6.82%，and 19.32% of patients，respectively. The level of inflammatory index procalcitonin was generally normal，while the level of C-reactive protein was increased. There were no obvious abnormalities in the indexes of coagulation function and fibrinolysis. The proportions of patients with normal CD3+T，CD4+T，CD8+T，CD16/56+NK cells，and CD19+B cells were 62.07%，60.92%，65.51%，73.26%，and 95.35%，respectively，and reduced in 32.18%，34.48%，27.59%，24.42%，and 4.65% of patients，respectively. Conclusion：Some laboratory indexes of patients with COVID-19 showed characteristic changes at first admission，which can provide preliminary clinical judgment，comprehensive assessment of the patient’s condition，and provide important reference based on nucleic acid detection.