Food insecurity is still a challenge in some remote and mountainous areas in China. When studying the impact of climate variability on food production, we should pay even more attention to the rainfed area. This is because the larger part of agriculture is the rainfed one and climate variability has more negative impacts on the rainfed agriculture than on the irrigated one. The traditional dry farming practices based on the principle of storing as much rain in the soil as possible and making best use of soil water could not bridge the gap between the time that the corp needs water and the time that rain occurs, so its effects on enhancing food production under climate variability is limited. Combining artificial water supply from rainwater harvesting systems with the traditional dry farming practices is an innovation in water management in rainfed agriculture. Experiences in the recent two decades indicate that rainwater harvesting irrigation can well mitigate the drought caused by the climate variability and bring the rainfed agriculture to a new level.