With the increasing output of coal fly ash (CFA) and garden waste, it is of great significance for environmental protection and resource utilization to establish if it can be recycled. The saline soil is widely distributed in the coastal areas of northern China, with high salt content and poor physical and chemical properties, which seriously affects the development of local agriculture and forestry and causes the waste of arable land. If CFA and garden waste compost (GWC) can be applied to saline soil improvement, it not only improves the local soil problem, but also helps environmental protection. Leaching salt is an important measure to reduce salt content in saline-alkali soil. The purpose of this study was to explore the effect of CFA and GWC on salt leaching of coastal saline-alkali soil through a soil column simulation test. The use of CFA and GWC promoted leaching and reduced leaching time. The addition of CFA and GWC to the soil suppressed the increase of HCO₃^- and CO₃^2- during leaching, but increased the salt ion content of the soil after leaching. The addition of CFA to the soil reduced the ion retention of GWC in the soil, but the application of CFA and GWC had no significant effect on the leaching sequence of salt ions. CFA and GWC added to the soil improved the physicochemical properties and the quality of saline soils, but GWC was less effective than CFA in improving soil physicochemical properties. Application of CFA reduced the leaching time of soil salt ions by about 25%, as well as reduced the pH, EC, SAR, and total salt ion content of the soil by 2.18%, 20.83%, 56.63%, and 38.95%, respectively.