Building 3-Dimensional model for simulating the shape, structure and sizes of human body according to ages and sex is basement for designing and manufacturihg Mannequin applied in costume design in industrial production. This paper presents research results of 3D scan technology and reverse design technique which are used to make 3D data set simulating shapes, structures and sizes of the boys' body at the age of primary school in Hanoi. In the research process, the authors specified standard sizes and set of 'parameters of standard dimensions of boys at the age of primary school in Hanoi, chose children who had the suitable body dimensions with set of parameters of standard body dimensions, constructed set of 3D data presenting children's body by 3D scanner made of [TC]2, chose 3D digitized data simulating the boys' body suitable with set of parameters of body dimensions of optimal sizes. Applying reverse design technique and Rapid Form XOR3 software to construct 3D model simulating body shape, structure and sizes based on white light 3D scan data.