The invention provides a method for controlling release of internal phosphorus by injecting an adsorbing material into sediment. The method comprises steps as follows: firstly, sludge of a water purification plant is filtered with an iron screen, then dried, crushed, sieved and fired, then calcium peroxide powder of 100 meshes is mixed, the mixture is evenly mixed with a stirring machine, and the adsorbing material is obtained; the adsorbing material is injected to the to-be-repaired sediment as follows: when the total phosphorus content of the sediment is smaller than or equal to 500 mg/kg in terms of every square meter of the sediment, an adsorbing material column sample is injected in the central point of the plane of the sediment; when the total phosphorus content of the sediment is larger than or equal to 500 mg/kg but smaller than or equal to 1,000 mg/kg in terms of every square meter of the sediment, adsorbing material column samples are injected in four points of the plane of the sediment; when the total phosphorus content of the sediment is larger than or equal to1,000 mg/kg in terms of every square meter of the sediment, adsorbing material column samples are injected in four points of the plane of the sediment; the injection depth reaches the background. With the method, the purpose of controlling release of the internal phosphorus can be achieved.