20世纪初,在贝利和克莱因等数学家的大力倡导和推动下,函数进入了中学教材。函数概念是数学最重要的概念之一。从高中教材中一道例题出发,以对应关系中“一对多”的情况为突破口,对函数概念进行了再理解。 Early 20th century, Bailey and Klein and other mathematicians advocated and promoted, the function entered the secondary school textbooks. Function concept is one of the most important concepts in mathematics. Starting from an example of high school teaching materials, we take a “one to many” correspondence as the starting point to understand the concept of function.