The purposes of this study were to investigate the development of physique and physical fitness of Chinese children and adolescents. This is a part of the third year report of a three year continual study on physical and psychological development of Chinese school pupils. 　　Besides 565 students for the longitudinal study on physique and physical fitness, there were 1962 subjects sampled from the first year of primary school to the third year of junior high school as the second time to use the cross-sectional approach to investigate the development of physique. This study also investigated the stability of the change of somatotype. 　　The main findings were as follows: 　　1. According to the study of physique, girls arrive at the growth spurt of puberty nearly two years earlier than boys, and the growth of body height increases more stably than weight. 　　2. The somatotype of the students is rather stable, almost three fourth of the students remain the same type in three years. 　　3. There are almost steady increase in seven items of physical fitness in both sexes (except girls in flexed-arm-hanging) during the school years. 　　4. The study results of longitudinal approach and cross-sectional approach of both the development of physique and physical fitness are rather consistency, but the longitudinal approach shows the tendency of development more clearly than the cross-sectional approach.