NOVELTY - Method for improving saline-alkaline soil involves applying phosphogypsum powder on the surface of saline-alkaline soil, processing using rotary cultivator, covering film for 14-30 days, removing film, leaching, applying sugarcane bagasse adsorbent, polysilicic acid ferric sulfate, polymerized iron-aluminum silicate and diatomaceous earth on the soil, processing using rotary cultivator, covering film for 5-10 days, leaching, applying fermented material prepared using Fusarium, mushroom bran and effective microorganism inoculant, and processing using rotary cultivator.    USE - Method for improving saline-alkaline soil (claimed).    ADVANTAGE - The method reduced content of salt and pH value of saline-alkaline soil, and effectively improves soil structure of saline-alkaline soil and content of organic substance of saline-alkaline soil.    DETAILED DESCRIPTION - Method for improving saline-alkaline soil involves adding sugarcane bagasse to an autoclave, adding ethanol and water, sterilizing, filtering, mixing filter residue with nitric acid, adding water to adjust pH value to 5-5.5, adding cellulase enzyme, performing enzymatic hydrolysis process, drying obtained material, pulverizing, obtaining sugarcane bagasse adsorbent, adding Fusarium, mushroom bran and effective microorganism inoculant to a fermentation tank, adjusting moisture content to 50-60%, fermenting for 12-15 days, obtaining fermented material, crushing phosphogypsum into 100-200-mesh fine powder, adjusting saline-alkaline soil moisture content to 40-50%, applying phosphogypsum powder in an amount of 350-1500 kg/acre on the surface of the saline-alkaline soil, processing using rotary cultivator, covering a film for 14-30 days, removing film, leaching, adjusting topsoil moisture content to 60-80%, uniformly applying sugarcane bagasse adsorbent, polysilicic acid ferric sulfate, polymerized iron-aluminum silicate and diatomaceous earth on the soil, processing using rotary cultivator, covering a film for 5-10 days, removing the film, leaching, uniformly applying fermented material, and processing using rotary cultivator.