The major purpose of this study is to discuss the development of the Chinese children's concept of point-symmetry. This study includes probing the children's state of cognition which related to symmetric concept, comparing the conceptual differences among children, observing children's types of thinking, and analysing children's possible error. It is the goal of this study, providing elementary school teachers with reference, when they teach and revise the mathematics curriculum. The subjects were chosen from the middle graders of Chung-hsiao Elementary School in Taichung city, the materials of task were especially designed, and interviews were taken individually. The important data were collected mainly by the "quality analysis". Through observing these children's reaction, while the middle graders were recognizing the characters of point-symmetry-figures, it is found that they still need to rely upon operating picture card. Furthermore, the majority of these children dealed with the point-symmetry-figure as same as the line-symmetry-figure, it reveals that this type of response is similar to the phenomenon of binary reversion. The researchers have paid more attention upon observing each child's visually-moderated sequences, in order to trace the state of the development of the concept. It is revealed from the result: most of the middle graders stay at the recognition level, according to van Hiele Level; a few of the forth graders have known to apply the character of symmetry for operating figures, and they reached to the analysis level.