Abstract: Sustained supply of sufficient water resources and quality food is essential for the continuity of human being society. Water security is fundamental for food security. Continuously increasing the utilization efficiency of agricultural water resources is the only way to ensure future water and food security. This paper focused on the basic issues of water and food security, including the definitions, present and future states at global and national scales, water resources supporting strategies for national food security, and development of water-saving agriculture in China. The key issues of water and food security were reviewed and discussed, including efficient crop water consumption, high-efficiency control and management of water resources, ecological and environmental effects of agricultural water consumption processes and responses to flood and drought events. Then four major research fields were summarized, including: 1) ideal crop water consumption mechanisms and multi-process synergy control mechanisms, 2) multi-scale water cycle and accompanying processes at irrigation district scales with highly intensive human activity, 3) mutual feedback mechanisms of food production-water resources-ecological process systems, and 4) disaster-causing mechanisms and early-warning mechanisms of agricultural drought and flood disasters.