Research on characteristics of upper body development of girls in primary schools in Hanoi is based on cross-section method and direct measure. Objects of study are similarly selected and biological statistics and SPSS software are used to process data. Result of the research shows that the height, the weight, the size as well as the width and the thick of bust, belly and hips increasing according to the age, but the increase rate depends on the age. The rate increase fast during the age of 10-11. The belly does not change much while the bust and hips develop a lot, the growth rate is 5.6 percent. The body is pretty thin. When they are older, the shape of body turn into the hourglass shape. This is the foundation to research on designing clothes which are suitable to the characteristics of body of school children now.