Objective To investigate the diffusion trend of Armigeres subalbatus and analyze its potential geographic distribution in China. Methods The trend analysis of diffusion and population dynamics were carried out based on three aspects including literature reports,information of museum specimens and new collection records from our field survey. To compare the potential geographic distribution,two ecological niche models were constructed by Maxent software based on the geographic presence occurrence data and 20 environmental variables. The final models were evaluated with the receiver operating characteristics curve(ROC). The analyses of variable contributions were confirmed by using the Jackknife method. Results The populations in Weifang and Weihai,Shandong Province were reported for the first time. The results showed that this species was spread to the Palaearctic Northern Region and reached 42° north latitude regions. In some areas,it gradually developed into a dominant species. A total of 294 georeferenced occurrence points of A. subalbatus were found out. Two predictions of Maxent models were established based on the presence occurrence data in 2000 and 2016,respectively. The results showed that the current distribution range of A. subalbatus had been significantly northward expanded compared with 2000. It means that the potential suitable area gradually spread northward. The ROC analysis results showed the AUC values were 0.980 and 0.982,and it indicated that the models had a high reliability. The Jackknife method displayed that the precipitation of warmest quarter,precipitation of wettest month and precipitation of wettest quarter were the dominant environmental variables that mainly contributed to the distribution of A. subalbatus. Conclusions A. subalbatus distribution gradually spreads northward,and climate warming is probably the main reason for the diffusion. It could affect the local mosquito species composition and increase the risk of mosquito-borne disease transmission.