This paper was made for the purpose of analyzing primary school and Kindergarten child`s concept formation about projective Space. Using clinical method, this research was executed to 351 children at Suwon Kwon-neon primary school and Kindergarten in Kyung Ki Do. Research results according to the problem were as following (1) The concept formation about projective Space is faster than that of piaget`s research. But fluent concept formation ability doesn`t reach piaget`s. (2) Sex difference of concept formation about projective space is as follows : boy`s concept formation is faster than girl`s.