The invention discloses a saline-alkali soil improving method. The method includes the steps of leveling the terrain of selected saline-alkali soil, laying salt disc elimination harge closed underground pipes, installing a bitter water desalting system to desalt crude water and collected salty water of the saline-alkali soil to provide fresh water for irrigation salt content restraining and irrigation, primarily conducting primary salt elimination on the saline-alkali soil through irrigation salt content restraining, adjusting the soil structure through a saline-alkali soil modifier, providing trace elements required by plants, planting salt-tolerant plants for further reducing salt content, conducting underground salt elimination through the combination of drip irrigation-micro jet devices and the salt-tolerant plants, and executing information maintenance management on the area of the saline-alkali soil. The method integrates biology, physics, chemistry and water conservancy methods, and is small in water resource consumption, rapid in effect, not prone to salt returning and more beneficial to plant growth.