This paper studied two kinds of urban water-green combined systems, where mosquito larvae were found, hoping to provide a theoretical basis for urban mosquito control and prevention through the comparison and analysis of different factors. The results showed that the larval density in the outer-ring greenbelt drainage system, whose water quality was below Class Ⅴ, was significantly higher than the larval density in the riparian zone of Changfeng Park with Class Ⅳ water (p < 0.05); this can be attributed to the relatively poorer water quality and plant cover, fewer predators, weaker illumination, and so on. The larval density reached 157.6 per dip in peak season in the west outer-ring greenbelt drainage system. Because of the relative closure and overcrowded vegetation, mosquito larvae in the Calamus Pit only appeared in late spring and early summer, but with high density. The larval density was low in Lotus Pond owing to the open water surface and the connection with Yinchu Lake. The rock-filled revetment of Tiebi Hill provides shelters for larval survival. Both areas had a risk for mosquito-borne diseases, requiring relevant measures such as filling, revetment restructuration, and environmental improvement. The overwintering form of Culex pipiens pallens are adults and the time difference of the larval presence can be attributed to the availability of blood meal. The larval density was negatively correlated to DO and chlorophyll-a concentration, but positively correlated to NH₄⁺-N, TP, BOD₅, and COD_Mn.