(1) Background: Overseas imported dengue fever is an important factor in the local epidemic of dengue fever in mainland China. Therefore, in order to effectively prevent and control the local epidemic of dengue fever in mainland China, the epidemiological characteristics and temporal-spatial distribution of overseas imported dengue fever cases in provinces where dengue fever is endemic in mainland China are explored. (2) Methods: Through the infectious disease report information management system of the Chinese Disease Prevention and Control Information System, we sorted out overseas imported dengue fever cases in local outbreaks of dengue fever in mainland China from 2005 to 2019. Using Excel 2016 to sort out the data and draw the epidemic curve and population characteristic distribution of overseas imported cases in each province. Using ArcGIS 10.7 and SaTScan 9.5, we analyzed the temporal-spatial distribution of dengue fever in provinces where dengue fever is outbreak in mainland China. (3) Results: A total of 11407 imported cases, mainly from Southeast Asia, were recorded from 2005 to 2019 in 13 provinces, of which 62.08% were imported into Yunnan and Guangdong provinces. Among the imported cases, there were more males than females, mainly from 21-50 age group. 59.18% of the cases were farmers, businessmen, housework or unemployed. The hot spots were concentrated in parts of Yunnan and Guangdong provinces. Meanwhile,we found the clustered areas were expanding northward. (4) Conclusions: Focus on the publicity and education of dengue fever prevention knowledge among men, 21-50 years old, farmers, business services, housework or unemployed professionals. Further improve the awareness of the prevention and control of imported cases in border areas and economically developed cities. At the same time, the northern region cannot relax its vigilance.