Soil erosion and low use efficiency of natural resources in the agro-pastoral ecotone in northern China have become severe problems especially under climate change,which threatens local food security. Concerning the problems existing in rain-fed agriculture in the agro-pastoral ecotone in northern China,we discussed how intercropping improves vegetation cover and roughness to reduce soil wind erosion and nutrient leaching; to accelerate the decomposition of organic matter to improve soil fertility; and to increase resource use efficiencies and yields by temporal and spatial distribution of canopy and root structure and the interaction of different crop combinations. The limiting factors of the intercropping on crop productivity and the mechanisms of interspecific interactions were analyzed. Future researches should focus on the effect of climate change on potential yield and soil fertility of intercropping systems. The combination of field experiments and crop models,i.e. process-based crop simulation models and functional-structural plant models, would be helpful to explore the mechanism of efficient resource use at organ level and to illuminate how intercropping could mitigate climate risk at regional level.