A dosing control method for micro-flocculation in ultrafiltration, comprising: 1) setting a preset value of a first differential pressure before an initial filtration-backwash and a preset value of a second differential pressure before a final filtration-backwash in each chemically enhanced backwash cycle according to a work condition and quality of raw water; 2) calculating an allowable differential pressure before an N th filtration-backwash between the initial filtration-backwash and the final filtration-backwash according to the preset value of the first differential pressure and the preset value of the second differential pressure; 3) starting a ultrafiltration and chemical dosing process; 4) obtaining a predicted differential pressure before the N th filtration-backwash according to a differential pressure curve plotted based on online filtration differential pressure data during the N th filtration of the ultrafiltration system; 5) comparing the predicted differential pressure with the allowable differential pressure before the N th filtration-backwash to obtain a first judgement result, and recording a duration that the first judgement result remains unchanged, wherein the first judgement result includes the predicted differential pressure before the N th filtration-backwash being greater than the allowable differential pressure before the N th filtration-backwash, or the predicted differential pressure before the N th filtration-backwash being smaller than or equal to the allowable differential pressure before the N th filtration-backwash; 6) if the first judgement result indicates that the predicted differential pressure before the N th filtration-backwash is greater than the allowable differential pressure before the N th filtration-backwash, and the duration that the first judgement result remains unchanged is less than a first preset duration, performing a dosing operation at a preset dosage; 7) if the first judgement result indicates that the predicted differential pressure before the N th filtration-backwash is greater than the allowable differential pressure before the N th filtration-backwash and the duration that the first judgement result remains unchanged is no less than the first preset duration, performing a dosing operation at an increased dosage; and 8) if the first judgement result indicates that the predicted differential pressure before the N th filtration-backwash is smaller than or equal to the allowable differential pressure before the N th filtration-backwash, and the duration is no less than a second preset duration, stopping the dosing operation. 1) setting a preset value of a first differential pressure before an initial filtration-backwash and a preset value of a second differential pressure before a final filtration-backwash in each chemically enhanced backwash cycle according to a work condition and quality of raw water; 2) calculating an allowable differential pressure before an N th filtration-backwash between the initial filtration-backwash and the final filtration-backwash according to the preset value of the first differential pressure and the preset value of the second differential pressure; 3) starting a ultrafiltration and chemical dosing process; 4) obtaining a predicted differential pressure before the N th filtration-backwash according to a differential pressure curve plotted based on online filtration differential pressure data during the N th filtration of the ultrafiltration system; 5) comparing the predicted differential pressure with the allowable differential pressure before the N th filtration-backwash to obtain a first judgement result, and recording a duration that the first judgement result remains unchanged, wherein the first judgement result includes the predicted differential pressure before the N th filtration-backwash being greater than the allowable differential pressure before the N th filtration-backwash, or the predicted differential pressure before the N th filtration-backwash being smaller than or equal to the allowable differential pressure before the N th filtration-backwash; 6) if the first judgement result indicates that the predicted differential pressure before the N th filtration-backwash is greater than the allowable differential pressure before the N th filtration-backwash, and the duration that the first judgement result remains unchanged is less than a first preset duration, performing a dosing operation at a preset dosage; 7) if the first judgement result indicates that the predicted differential pressure before the N th filtration-backwash is greater than the allowable differential pressure before the N th filtration-backwash and the duration that the first judgement result remains unchanged is no less than the first preset duration, performing a dosing operation at an increased dosage; and 8) if the first judgement result indicates that the predicted differential pressure before the N th filtration-backwash is smaller than or equal to the allowable differential pressure before the N th filtration-backwash, and the duration is no less than a second preset duration, stopping the dosing operation.