It is a consensus among scholars at home and abroad that a good level of physical fitness has a positive impact on adolescents' physiological and psychological health. Adolescent physical health indicators are not only related to the risk of cardiovascular diseases, but also play an important role in improving adolescents' academic performance. Adolescent physical health indicators are not only related to the risk of cardiovascular diseases, but also play an important role in improving adolescents' academic performance. Identifying changes in adolescent physical health indicators is not only conducive to Identifying changes in adolescent physical health indicators is not only conducive to understanding their health status, physiological characteristics and individual differences, but also can provide a basis for adolescent talent identification and triage. Changes in the physical fitness of adolescents continue to improve with their age, and there are significant gender differences in the changes. Changes in the physical fitness of adolescents continue to improve with their age, and there are significant gender differences in the changes. In the age group of 12-13 years, males show a more significant rate of development in speed, aerobic and strength than females . This study is to track the physical fitness indicators of 12-15 year old adolescents in China, and to evaluate the stability of the changes in the indicators at different testing nodes of adolescents. This study is to track the physical fitness indicators of 12-15 year old adolescents in China, and to evaluate the stability of the changes in the indicators at different testing nodes of adolescents, with a view to providing reference for the improvement of the evaluation standard of physical fitness of adolescents in China, the reform of school physical education curriculum, and the establishment of students' physical fitness and health records. The following is a summary of the findings of the study.