The invention relates to a preparation method for an anti-pollution modified polyether sulfone nanofiltration membrane. The method comprises the following steps of: directly sulfonating polyether sulfone serving a membrane material with chlorosulfonic acid by taking sulfonated polyether sulfone and Pluronic F127 as a membrane modifying agent and taking a polar organic solution as a solvent to obtain sulfonated polyether sulfone; dissolving polyether sulfone, sulfonated polyether sulfone and Pluronic F127 into the polar organic solution, and stirring to uniform state in a water bath at the temperature 60 DEG C to form a membrane casting liquid; and obtaining a wet modified polyether sulfone nanofiltration membrane by using a phase conversion method, and naturally drying the wet modified polyether sulfone nanofiltration membrane in the air to obtain a modified polyether sulfone nanofiltration membrane. The modified olyether sulfone nanofiltration membrane prepared with the method has the advantages of high flux, high anti-pollution capability, simple membrane preparing process and mild condition, and can be applied to membrane separating processes such as sea water desalinization, dye desalting, sewage treatment and the like.