To investigate the synergistic purification of photocatalysis and water recycling for nitrogen, phosphorus and imidacloprid pollution, three groups of ecological floating bed systems including the blank control, water circulation and photocatalytic water circulation, and six treatment groups were designed for the purification of two kinds of simulated water(nitrogen-phosphorus (NP) receding water and NP-imidacloprid complex polluted receding water).The experimental results showed that the water circulation enhanced the removal of nitrogen, and the removal rates of ammonia and nitrate nitrogen in the water of the water recirculating floating bed for the receding water purification of nitrogen and phosphorus increased by 5.5% and 27.1%, respectively, compared with the blank control floating bed after 7.d. The addition of photocatalytic purification technology could accelerate the nitrification of ammonia and nitrate nitrogen, and the removal rates of ammonia and nitrate nitrogen in the water of the water recirculating floating bed for the purification of nitrogen and phosphorus retreat water increased by 26.2% and 20.3%, respectively, compared with the blank control floating bed. Imidacloprid affected the purification efficiency of nitrogen and phosphorus in a water circulating floating bed. The TiO2 composite photocatalytic ceramic pellets had a good oxidative degradation effect on imidacloprid and a significant purification effect on the compound pollution of nitrogen, phosphorus and imidacloprid. The photocatalytic water recirculation floating bed purified 58.2% of imidacloprid in the compound polluted return water, and the removal rates of ammonia nitrogen, nitrate nitrogen and phosphate in the water body were increased by 72.4%, 15.0% and 14.8% respectively compared to the water recirculation floating bed without the addition of imidacloprid.