Abstract: Saline-alkali land represents the largest cultivated land reserve in China. Accurately assessing the cultivation suitability of saline-alkali land can facilitate the rapid and effective management of saline-alkali land based on local conditions, thereby promoting the sustainable development of agriculture. Using the Landsat satellite data, this study analyzed the evolutionary pattern of soil salinization in the Songliao Plain between 1985 and 2020. Considering the salinization changes of cultivated areas in the saline-alkali land, this study established the CART-XGBoost model for assessing the cultivation suitability of existing saline-alkali land in the region. The results show that the saline-alkali land in the Songliao Plain covered an area of 3.85×10⁴ km² in 1985, which was reduced to 2.53×10⁴ km² by 2020. The CART-XGBoost model yielded an accuracy of above 0.61, representing a 30% improvement in suitability assessment accuracy compared to the global XGBoost model. The cultivation suitability of saline-alkali land was classified into four levels: high suitability, moderate suitability, low suitability, and unsuitability. The saline-alkali land, which is moderately suitable for cultivation, covers the largest area that totals 109 91.18 km², predominantly distributed in Baicheng, Jilin Province and Daqing, Heilongjiang Province. The saline-alkali land unsuitable for cultivation is primarily distributed in some areas of Anda City, Heilongjiang Province. Overall, the CART-XGBoost model for assessing the cultivation suitability of saline-alkali land provides a scientific basis for the conversion of saline-alkali land into cultivated land.