The turbidity degree of surface water in the rainy season will change with the change in rainfall, and the predictability and flexibility of water sources lead to the difficulty of purifying suspended solids. Therefore, the key technologies for purifying suspended solids in turbid surface water under the influence of the rainy season are studied. Select a small pool in a certain area as the research object, test the basic water quality indicators of the water source, measure the particle size distribution of the raw water according to the characteristics of suspended particles in the raw water, prepare the flocculant organic solution with a concentration of inorganic to organic ratio of 10:1, measure the turbidity of the water sample, flocculate the suspended solids in the raw water, and use ultrafiltration technology to purify the suspended solids in the raw water in the study area. The Daphnia magna was separated and purified, and the purification test of suspended solids in turbid surface water in the study area was carried out according to the prepared flocculant. The test results show that the use of PAM-PAM composite flocculant can achieve a better purification effect of suspended solids in turbid surface water under the influence of the rainy season, and the flocculant is combined with ultrafiltration. When the dosage of flocculant is 4mg/L, the removal rate of suspended solids is better. For suspended solids with smaller particle sizes, the combination of flocculant ultrafiltration and Daphnia magna can purify a large number of suspended solids in surface water bodies. A good purification effect is achieved.