The purpose of this study is to analyze the characteristics of imported infectious diseases in Shanghai between 2012 and 2019 and to provide a basis for more efficient prevention and control. A retrospective and descriptive analysis was conducted for all infectious cases identified as overseas imported in a hospital in Shanghai. The results demonstrated that a total of 305 cases of imported infectious diseases were listed, including malaria, dengue fever, tuberculosis, measles, hepatitis A, hepatitis E, typhoid fever, Ebola hemorrhagic fever, HIV infection, yellow fever, diphtheria, and recessive syphilis. 225 cases were malaria (73.77%) and 68 cases were dengue 22.30%. Both malaria and dengue fever were imported throughout the year, with June, September, and November being the peaks of imported malaria, and June-August being the peak of dengue fever input. Among the pool of imported cases, Chinese nationals were affected more than foreigners, and males more than females. Most of the patients were young and middle-aged, the main occupations were business services and workers, and the main origin of imports was Africa. It was concluded that mosquito-borne infectious diseases such as malaria and dengue fever in summer and autumn are major concerns for imported infectious disease. Health education for labor and tourism groups in Africa and Southeast Asia should be strengthened, and other measures such as case supervision, anti-mosquito and reducing the number of second-generation cases should be taken to better prevent imported infectious diseases.