The invention discloses a powdery saline-alkali soil water-retention slow-release fertilizer. The technical scheme of the powdery saline-alkali soil water-retention slow-release fertilizer has the key point that the ingredients of the powdery saline-alkali soil water-retention slow-release fertilizer consist of high-viscosity attapulgite clay powder, acidized attapulgite clay powder, ardealite, ammonia sulfate, calcium superphosphate, potassium sulphate, sulfuric acid, super absorbent resin and microelement mixture, and the ingredients of the powdery saline-alkali soil water-retention slow-release fertilizer are smashed after being stirred and are packed as the finished product of the powdery saline-alkali soil water-retention slow-release fertilizer. The powdery saline-alkali soil water-retention slow-release fertilize is acidic, the alkalinity of soil can be lowered, calcium ions contained in the fertilizer can be used for replacing sodions on a saline alkali soil colloid, so that the content of the soil exchangeable sodions is lowered, and a purpose of improving the saline-alkali soil is achieved. The powdery saline-alkali soil water-retention slow-release fertilizer contains a great quantity of nitrogen, phosphorus and potassium and various trace elements, has the functions on slow release of fertilizer efficiency and water retention and is suitable for topdressing on the saline-alkali soil, and necessary nutritional ingredients for plant growth can be provided.