Objective：To summarize the clinical and imaging characteristics and differences between coronavirus disease 2019 （COVID-19） and common pneumonia，and to improve differential diagnosis ability. Methods：Retrospectively collected the clinical and imaging data of 37 cases of early-stage COVID-19 and 40 patients with early-stage common pneumonia（not COVID-19） from January 25，2020 to February 16，2020. The clinical manifes－tations，main laboratory and CT findings of the patients were summarized and compared. Results：The clinical manifestations of COVID-19 were similar to those of patients with common pneumonia，but the former usually had a clear epidemiological history and were less likely to have an increase in white blood cell count，absolute neutrophil counts，and C-reactive protein（P<0.001），while those with decreased absolute lymphocyte counts were more common（P<0.05）. The lesions of early-staged COVID-19 and common pneumonia patients were mainly ground glass opacity（GGO）（89.2% vs. 90.0%，P=1.000）. In patients with COVID-19，the lesions were mainly round or semicircular（19，51.4%），followed by small patchy（15，40.5%），and the subpleural area was mainly involved（25，67.6%）. In patients with common pneumonia，the lesions were mainly patchy GGO with consolidation（21，52.5%） and GGO was the main component（17，81.0%），followed by single or multiple small patchy GGO（11，27.5%），and they mainly involved the entire lung segments or subsegments（31，77.5%）. Reticular shadow（16，59.3%） and multiple nodules（27，77.1%） were frequently seen in heterogeneous GGO in 27 COVID-19 patients and 35 patients with common pneumonia，respectively. Compared with COVID-19，internal bronchial wall thickening（42.5% vs. 8.1%，P=0.001） and blurred boundary（75% vs. 45.9%，P=0.009） were more common in lesions of common pneumonia. Conclusion：The pulmonary lesions of early COVID-19 and common pneumonia were mainly GGO，while the former is mostly round or patchy，mainly involves subpleural region，and frequently has internal reticular shadow and clear boundary，the latter is mostly patchy，mainly involves the entire lung segment or subsegment，and usually had internal consolidations，nodules and thickened bronchial wall，and blurred boundary. Imaging combined with patient’s clinical information and laboratory examinations can help distinguish these two diseases.