Abstract: One of the primary reasons for frequent algal blooms are the release of phosphorus and the algae recovery in sediments.Therefore,the deposits of the eutrophic Shanzi Reservoir in Fujian Province were taken as the research object and laboratory simulation experiments were carried out to explore the inhibitory effect of new phosphorus-locking agent(NP)on the release of phosphorus in the sediments and the recovery of algae.The experimental results showed that the addition of NP increased the total phosphorus(TP)and the calcium-bound phosphorus(Ca-P)of the deposit by 10.8% and 15.9%,respectively.The theoretical amount(NP:P=100:1)of the NP's inhibition rate only reached 34.0% during the experiment.Adding twice as much NP improved phytoplankton germination inhibition in sediments by 69.2%,but the cost was higher and the ecological risk of heavy metal residues had increased,the method of combining 60 mg/L Polyaluminum Chloride(PAC)or Diatomaceous earth(DIA)with the theoretical amount of NP also had a better effect and changed the structure of the phytoplankton community in water.Therefore,the algae inhibition rate,the cost,and ecological risks should be comprehensively considered and choosing a suitable combination of NP and coagulants could have a better effect to treat eutrophic water.