Abstract: Objective This paper analyzed the changes of the physical development of students in ru- ral area of Chang' an District during the ten years from 1990 through 1999. Methods Stratified and cluster sampling method were applied to collect two parameters (body height and weight) of students of every primary school and high school in Chang' an District. Results The physical development of ru- ral students in Chang' an District improved significantly during the ten years. In the decade, the mean height of male and female of rural students aged 7 —18 years old increased 2. 23cm and 1. 93cm re- spectively while the average of their weight increased 1. 74kg and 1. 21kg respectively. But these values increased were lower than that of rural students in the national investigation of China. The maximum annual increment and the maximum annual incremental rate in 1999 were lower than those in 1990. The peak height velocity and the peak weight velocity of female students in 1999 appeared 0. 77 and 0. 32 year earlier than in 1990 while that of the male student were 0. 52 and 0. 6 year later respectively. Couclusions The physical cevelopment of rural students in the area was still progresing as that shown in secular growth trend, but the velocity became slower. The growth potential of the students remained to be brought into full play.

Key words: Growth; Development; Secular growth trend; Rural student