Abstract: In this study,Dongyaxi Reservoir in Sanming City,Fujian Province was taken as the research object.The effect of ecological restoration of the micro-nanometer aeration project in four seasons was evaluated by comparing the water quality and phytoplankton characteristics between the aeration area and non-aeration area.The effect of micro-nanometer aeration project in Niulingku Bay was evaluated in 2017.The results showed that the dissolved oxygen in the water body bottom layer of the aeration area was 0.3~1.1 mg/L higher than that in the non-aeration area.The reduction rate of total phosphorus concentration was 14.0%~29.1%.Aeration may have an effect on promoting the reduction of total phosphorus by precipitation,adsorption,adhesion and other removal,while phosphorus is easy to be adsorbed by minerals rich in Fe,Al and Ca.Total nitrogen concentration was not markedly reduced,it might be that different aeration conditions affect the removal efficiency of ammonium nitrogen and nitrate nitrogen,which was also related to the background value of nitrogen in water.In addition,the reduction rate of chlorophyll and algae cell abundance in water was 25.1%~51.0% and 16.9%~37.9%,respectively.In summer,the reduction of chlorophyll and algae cells achieved the highest as 51.0% and 37.9%,respectively.Comparison between aeration area and non-aeration area showed that the reduction rate of the algae cell abundance was 16.9%~37.9%,the reduction rate of the Cyanobacteria was 14%~26%,the reduction rate of the green algae was 19%~51%,and the reduction rate of the diatom was 20%~36%,which indicated that the micro-nanometer aeration could inhibit the growth of the phytoplankton to a certain extent.The inhibitory effect of micro-nanometer aeration on algae growth might be due to the rapid extinction of algae caused by the inhibition of phosphorus released by microbial species of sediment and the increase of turbidity of water body.In the present study,the micro-nanometer aeration disc was placed at the bottom of the water body,and the effect of aeration on the growth of the algae was obviously inhibited due to the adsorption and fixing action of the bottom mud to the phosphorus.The results showed that the micro-nanometer aeration technology could control algae well in summer.As a new aeration technology,micro-nanometer aeration was widely used in the field of environmental pollution remediation because of its low investment,no secondary pollution and convenient operation and management.Micro-nanometer aeration technology could change dissolved oxygen in water body,restore and enhance microbial activity in water body,so as to purify water quality.It was a promising technique for ecological restoration of water source,which could be further studied by combining with other ecological indicators such as zooplankton.Water eutrophication was easy to erupt in spring and summer.When the temperature begins to rise gradually,considering the cost-benefit and other factors,the micro-nanometer aeration project can operate in spring and summer in order to inhibit the growth of algae,while in autumn and winter,aeration can be properly reduced in order to achieve the optimization of benefits.