Objective To investigate the population and density variation of malaria vectors in Zhejiang province, China, and to provide a scientific basis for malaria control strategy in post-elimination stage. Methods From 2012 to 2017, 14 to 18 malaria vector surveillance sites were set up in Zhejiang province. Mosquito population surveillance with the lamp trapping method from sunrise to sunset for 2 days (3 days in 2016-2017) was conducted once in each August. Density surveillance with the overnight human trapping method (usually from19:00 to 07:00) was conducted once in the beginning and late of July, August and September (from May to October in some surveillance sites from 2016 to 2017). All the surveillance spots were set between residential areas and mosquito breeding sites. All Anopheles mosquitoes captured were frozen and dead, and then morphologically identified, counted, and reported. Excel 2013 software was used to analyze the surveillance data. "Dituhui" website was used to draw the surveillance site distribution map online and R 3.5.1 software was used to draw the heat map. Results The results of lamp trapping method for mosquito population surveillance showed that the single vector of malaria transmission in Zhejiang province was Anopheles sinensis. Human trapping density surveillance showed that An. sinensis had been active in some areas in early May, and the density of An. sinensis peaked in late July 3.63 only/(person·h) and dropped to the lowest in late October 0.02 only/(person·h). The peak night activity of An. sinensis in Zhejiang province occurred between 20:00 and 21:00. According to the heat map analysis, although the density of An. sinensis was generally low in late September, the density rebounded in some areas in some years, and the peak time of density had been advanced to May and June at some surveillance sites in the south of Zhejiang province. Conclusion As the single vector of malaria in Zhejiang province, An. sinensis continuously exists, which makes the local transmission of malaria at potential risk. Therefore, continuous and standard vector surveillance needs to be consecutively carried out, and molecular biological technique should be used in the study of mosquito population and insecticide resistance related genes in the future.