Food availability and self-sufficiency are represented by food supply and production, and food trade is represented by the difference. The changes of dietary nutrition can be better reflected by converting calories per person per day. The study analyzes the situation of food trade during 1986-2013. The results show that global food trade volume increased 1.5 times in the past 28 years, and food production increased 0.75 times. The proportion of trade volume in the production increased by about 8%, which is equivalent to 7.9×108 t of food entering the international market and has become the key to improve the dietary structure. In the past 28 years, food availability and self-sufficiency rose, and most of the world's population reached the minimum level of 2200 kal. Food availability, self-sufficiency and trade volume all showed regional differences. Some countries of Africa and South Asia were low value areas. On the whole, the daily supply of calories and protein per capita increased. Low-income countries grew fastest, followed by middle-income countries, and high-income countries grew slowest. But some underdeveloped countries in Africa still did not meet the minimum standards of nutrition, and part of world's population was still suffering from malnutrition.