Dajiuhu wetland is a rare subtropical alpine in the central China. Dajiuhu wetland is the source of the Du River, a first-grade tributary of the Han River, and the wetland also serves as one of the important water conservation area of the middle routes of South-to-North Water Diversion Project. The human activities such as ditches digging, holes dredging and bog draining have led to severe degradation of ecological function and the shrinking of lake surface area in Dajiuhu wetland since 1986. After the implementation of 'the Dajiuhu wetland protection and ecological restoration project' from 2005 until present, we conducted a field survey on the phytoplankton community and lake trophic status from November 2014 to September 2015 to reveal the status quo post the restoration project. Trophic status indices showed the water quality was between mesotrophy and light eutrophication. The water eutrophication level decreased along the water flow direction. A total of 129 phytoplankton species belonging 8 phyla were observed. Scenedesmus quadricauda, Melosira granulate and Eunotia sp. were the common dominant species in November 2014, and Phormidium tenue, Chlamydomonas globosa Snow, Scenedesmus quadricauda and Fragilaria brevistriata in May 2015; Limnothrix redekei, Cylindrospermopsis raciborskii, and Chroococcus minor in September 2015. All the dominant species were α or β-mesosaprobity species. Redundancy analyses indicated that total phosphorus and total nitrogen were the key drivers behind this difference of the phytoplankton abundance, while water temperature and total phosphorus showed significant effects on phytoplankton biomass. Redundancy analyses further showed a positive relationship between total phosphorus and the abundance (and biomass) of Cyanophyta or Chlorophya.