In nature, each species exists for its own reasons. A certain number of predators and prey also need to maintain a balance in order to ensure the ecological balance of the whole nature. In recent years, due to the destruction of ecological environment and human hunting, the number of big gray wolves is decreasing day by day. Due to the lack of their constraints, herbivores on the grassland multiply in large numbers, causing damage to the grassland ecology. Therefore, human beings put forward the idea of protecting the gray wolf.