This study is to use the longitudinal approach to investigate the development of the second year (grade 2, 5 and 8) of physique and basic physical fitness of Chinese children and adolescents. The subjects are 648 in number selected from the same grade 1, 4 and 7 of the last year. 　　The main findings are as follows: 　　1. According to the measurement of the same subjects of the first years grade 1, 4, and 7, there are steady increase of body height, weight and sitting height in both sexes of three grades in the second year. 　　2. The increase of muscular strength of boys in grade 2, and flexibility, muscular power and endurance of girls in grade 8 have reached the level of significance (P<0.05). The increase of all other items of physical fitness in both sexes of three greads have reached the level of more significance (P<0.01). 　　3. The correlation between the items of physical fitnees can be divided into two groups: pull-ups, flexed-arm-hanging, sit-up, standing long jump and soft-ball throw for distance are in one group, and 50 meter sprint, shuttle run and endurance run are in another group. The correlation coefficients of the items in the same group are positive, but the correlation coefficients of the items between two groups are negative.