According to the survey, the staple food of the diet of the elderly with longevity in China is corn, wheat and other grains, and the non-staple food is mostly bean products, vegetables and fruits, supplemented by a small amount of poultry meat and game. Vegetarian food contains essential sugar, protein, fat, minerals and rich vitamins, which plays an important role in delaying aging, preventing senile diseases and improving health. Vegetables and fruits are alkaline foods. People usually eat more acidic food, which is easy to cause acid-base imbalance in the body and harmful to the body. Vegetarian food is very beneficial to human health, but eating more vegetarian food does not mean not eating vegetarian food. Reasonable diet conditioning should be based on vegetarianism and combined with vegetarianism in order to prolong life.