Abstract: Food supply and demand around the world is basically in a state of tight balance, but regional imbalances are obvious, and food shortages in some areas are still serious. Since 2000, the number of hungry people in the world has been declining significantly, but signs of rebound appear recently. In general, insufficient effective demand is an important factor to cause food insecurity around the world. Furthermore, trade only dominates a relatively small proportion of global food supply, thus it cannot fundamentally address food security issues. Besides, the potential productivity of the world’s food can conditionally meet the effective demand for future consumptions, however, multiple unfavorable factors, such as conflict and climate change, will continually challenge the world food security for a long time to come.