This study aimed at investigating the inner mechanism of young children's drawing activity. For this purpose, two kinds of drawing instruction were given to young children experimentally. Drawing activity is built up in the process of both recognizing and expressing an object. Recognizing response and expressing response are related to each other. In order to examine this relationship, three supplemental experiments were designed, in advance of the drawing instruction. In those experments some features of young cjildren's recognition and drawing were found:(1)The previous experiences concerned with the object significantly influence the contents of recognition and drawing of the object. (2)Usually young children don't pay attention to the "figure" attribute when they recognize an object. Consequently they feel difficulty in drawing an object, and the contents of their drawings are very poor. (3)If young children are given some effective instructions of an object, they can recognized the object systematically, and they can improve themselves in drawing. From these findings the following hypotheses were introduced. If young children are given some information of simple figures and they learn to see an object by imagining those simple figures, they will be able to recognize the object systematically and to draw an object similar to it. These hypotheses were examined through two kinds of experimental instructions. One was the training of drawing some simplified pictures composed of a triangle, square, and circle, the other was the training of drawing some realistic pictures. The children for these instructions were 20 boys and girls of H. Nursery School, who were 4 or 5 years old. These instructions were kept on doing during 6 months in the daily classroom situation. Instruction I:The children were trained to divide an objective picture composed of geometric figures into several parts first. For example, a picture of a horse is divided into face, neck, body, leg, etc. Then they were trained to draw every part from larger to smaller in turn, and finally to integrate the parts into the whole figure again. The objective pictures were set in front of each one of the children. During these training processes they were also asked to draw the objective pictures as similar to them as possible. Instruction II:The children were trained to divide an objective picture(realistic picture)into several parts on the basis of the knowledge acquired in the previous Instruction, then draw the picture while imagining parts to some simple geometrical figures. They were also asked to draw an picture as similar to an objective picture as possible. As the result of education, almost all the children who could't have drawn geometrical pictures and simple realistic pictures, cuold improve on their drawings and make their drawings quite similar to the objective pictures. Also they didn't find difficulty in drawing realistic pictures. The results supported the hypotheses. From the children's learning process of drawing objects, we might say that drawing activity is the process of coding and re-coding an object by simple geometrical figures as a primary unit.