The policy of "double reduction" clearly requires that primary and secondary schools should carry out a variety of popular science, style, art, labor, reading, interest groups and community activities. However, the present situation of extracurricular sports activities in primary and secondary schools in China is not optimistic. Through research, it is found that there is a common problem of "rigid content and form" in extracurricular sports activities in primary and secondary schools in China, and students feel boring and have low enthusiasm for participation. "Children's Fun Track and Field" is a track and field sport that integrates running, jumping and throwing according to students' physical and psychological characteristics. It integrates sports and entertainment, and the forms and contents of sports events are rich and more interesting. Therefore, under the background of "double reduction" policy, it is particularly important to vigorously develop children's interesting track and field events in extracurricular sports activities in primary and secondary schools in order to enrich the content and form of extracurricular sports activities in primary and secondary schools, stimulate students' interest in extracurricular sports activities and improve their enthusiasm for participating in activities. Research methods: By using the method of literature, we know the current difficulties and shortcomings of extracurricular sports activities in primary and secondary schools, as well as the origin and content of children's interesting track and field. Research conclusion: Extracurricular sports activities in primary and secondary schools in China are currently facing the dilemma of single content and form, which can be alleviated by developing children's interesting track and field in extracurricular sports activities in primary and secondary schools. The research suggests that the traditional track and field sports such as walking, running, jumping and throwing should be improved appropriately, so as to enrich its form and content and add interest, thus stimulating students' interest in extracurricular sports activities, improving students' enthusiasm for participating in activities, forming good physical exercise habits and promoting the healthy development of body and mind.