Context or problem Saline-alkali land, as a global ecological and agricultural challenge, has seriously threatened food security and ecological stability. Therefore, its improvement is essential. Salt barriers, due to their low cost and abundant material sources, are widely used to mitigate salinization. However, effects of salt barriers on soil salinity and crop yield under various environmental factors (e.g. soil texture, groundwater, and evaporation / precipitation) and salt barrier parameters (including material, thickness, and burial depth) remain unclear. Objective or research question Our study aimed to explore the effect of salt barriers on the improvement of soil salinity and crop yield and the mechanisms by which salt barriers enhance crop yield. Methods The present study synthesized data from 54 published articles to obtain 731 paired observations. Articles published before January 2024 were identified using the Web of Science and China National Knowledge Infrastructure platforms, based on keyword combinations such as salt barriers (e.g. soil interlayers) and salinization (e.g. soil salinization). The data were then subjected to extraction analysis. Results The meta-analysis revealed that salt barriers reduce soil salinity in the plough layer by approximately 26 % and increase crop yield by about 31 % (P < 0.05). Salt barriers made of organic or mixed materials, with a thickness < 10 cm and burial depth between 40-80 cm, showed the highest effectiveness in loamy soils where the evaporation to precipitation ratio is < 10 and groundwater depth is < 3 m. Salt barriers reduced soil salinity by lowering bulk density, which in turn enhanced crop yields. This process indirectly promoted plant growth by increasing soil nutrients. It should be noted that yield responses to salt barriers varied due to differences in irrigation, fertilization, tillage, and management. Nevertheless, the overall yield improvement remained significant and consistent, confirming the robustness of our meta-analysis. Conclusions The results suggest that salt barriers can improve saline soils by improving soil structure and nutrients, which may have the optimal potential in semi-arid and coastal areas compared to other regions. Implications or significance Future research should address microbial impacts, material durability, and mechanization compatibility to ensure the stable application of salt barriers. We recommend integrating this technology into regional saline-alkali land management through demonstration and large-scale promotion. Overall, this study offers a scientific basis for applying and scaling up salt barriers to support food security and sustainable agriculture.