Objective To analyze clinical and epidemiological characteristics of patients with coronavirus disease 2019 (COVID-19), further enhance the understanding on COVID-19. Methods Clinical data of 80 patients who were confirmed with COVID-19 in Zhuzhou City from January 20 to February 27, 2020 were analyzed retrospectively, including epidemiological condition, clinical characteristics, treatment and outcome. Clinical characteristics of patients in mild, common, severe and critically severe groups were compared. Results Of 80 confirmed patients, 22 (27.5%) were from Hubei epidemic areas, 58 (72.5%) were not from Hubei epidemic areas, 45(56.3%) of whom definitely contacted with infection sources and 13 (16.3%) had no definite contact history. There were 17 clustering epidemic involving 55 cases, 4 clustering epidemic imported from Hubei involving 9 cases, including 3 familial clustering; 13 local clustering epidemic involving 46 cases, including 10 familial clustering, 2 popular social gathering, and 1 friends' dinner gathering. The median age of 80 patients was 47.5 years; ratio of male to female was 1:1; 22 patients (27.5%) complicated with underlying diseases, the top three underlying diseases were hypertension, diabetes and coronary heart disease; there were 8(10.0%) mild cases, 55(68.8%) common cases, 11(13.8%) severe cases, and 6(7.5%) critically severe cases. The main clinical symptoms were fever, cough, expectoration, fatigue, headache, muscle ache and diarrhea. Compared with patients in mild and common groups, patients in severe and critically severe groups were older, with a higher proportion of diabetes and hypertension, and a higher proportion of dyspnea and respiratory frequency>24 times/minute, differences were all statistically significant(all P<0.05). 78 patients (97.5%) had normal or decreased white blood cell count, 20 (25.0%) had lymphocyte count <1.0×10⁹/L; lymphocyte count, lymphocyte percentage, hemoglobin and albumin in patients in severe and critically severe groups were all lower than those in mild and common groups (all P<0.05), differences in several blood indicators were all statistically significant. Nine patients(11.3%) had no pneumonia manifestations, 15 patients (18.8%) had unilateral lung involvement, 56 patients (70.0%) had bilateral lung involvement, all 17 patients (100.0%) in severe and critically severe groups had bilateral lung involvement. Conclusion Novel coronavirus(2019-nCoV) infection presents familial clustering, the proportion of older age and underlying diseases is higher in severe and critically severe groups, lymphocyte count of most severe patients decreased significantly, which can be used as a clinical early warning indicator.