The Olympic Mathematics is relatively in-depth, and the vigorous development of mathematical olympiad has greatly stimulated children's interest in learning mathematics, which has become a useful activity to guide them to be positive, explore actively and grow healthily. There are many practical problems, such as counting, graph theory, logic, pigeon hole principle and so on. To solve this kind of problem, it is generally necessary to analyze and summarize the mathematical significance of the actual problem, abstract the actual problem into a mathematical problem, and then use the corresponding mathematical knowledge and methods to solve it.