Objective To analyze the epidemiological and clinical features of coronavirus disease 2019 (COVID-19) infected with the Delta variant of SARS-CoV-2. Methods Retrospectively analyze the epidemiological and clinical features of 138 confirmed cases of COVID-19 infected with the Delta variant of SARS-CoV-2 from October 25, 2021 to November 19, 2021 in Yantan Branch of the Second People's Hospital of Lanzhou City. The epidemiological and demographic information, clinical symptoms, laboratory tests, chest CT, treatment and prognosis data were collected, with a final follow-up date of November 27,2021. Results As of November 19, 2021, a total of 144 confirmed cases of COVID-19 were reported in Gansu Province, of which 138 cases [65 males (47.1%) and 73 females (52.9%), aged 2-87 (42.7±21.0) years old, with the clinical classification of mainly common type (48.6%, 67/138)] were concentrically treated in the Yantan Branch of the Second People's Hospital of Lanzhou City. The transmission mode of the Delta variant of SARS-CoV-2 is mainly in confined spaces, with obvious tour group and family aggregation; screening the close contacts and community investigation are the main approaches of finding the infected persons; 86.2% (119/138) of confirmed patients have been vaccinated with the domestic inactivated COVID-19 vaccine. The most common clinical symptoms are cough (57.2%, 79/138), followed by sore throat (28.3%, 39/138), dry throat (24.6%, 34/138), and expectoration (21.0%, 29/138). Only 20.3% (28/138) of patients have fever, and 4 patients (2.9%) have decreased or lost sense of smell and taste. Laboratory tests showed that serum amyloid A and high-density lipoprotein cholesterol increased significantly.The Ct value of SARS-CoV-2 ORF1ab gene is 26.31±7.63, and N gene is 26.35±7.17. Chest CT fined that 71.3% (72/101) of confirmed patients showed bilateral lung lobes involvement, and the lesions are mostly located in the lower lobes of both lungs;the lesions are mainly flaky and patchy ground-glass opacities. All confirmed cases are treated with integrated traditional Chinese and Western medicine, mainly prone position ventilation and traditional Chinese medicine (TCM) treatment. The TCM treatment rate is 100% for severe cases. On the basis of respiratory support, nutritional support and anticoagulation, immunotherapy such as neutralizing antibodies are combined. Conclusions The main clinical features of COVID-19 infected by the Delta variant of SARS-CoV-2 in Gansu Province are low rate of fever, long time for viral nucleic acid turned to negative, low risk of severe illness after vaccination, the good therapeutic effect, no intubation, no extracorporeal membrane oxygenation (ECMO), and no deaths. "One person, one plan" personalized treatment with integrated Chinese and Western medicine can effectively control the progression of the disease and cure the disease.