The purpose of thìs study was to detennìne the influence of collage and assemblage techniques on the material use and special concept of students with mental retardation The subjects ìn this study were four selected students ìn the mìddle school section of specìal school for students wìth mental retardation in the ity of Mokpo, South\' Cholla Province. The art-activity program was bndùcted 20 times for 7weeks, three times a\' week, 50 minutes each. The 얀us 。f me expedrtlent was placed m giving a chance to utilized multiple öatenals and on enhancing the three-dimensional concept of space. The findings of this study were as below; First， the collage and assemblage techniques gave an impact on the 3 1 iterial use of students with mental retardation. As the art activity was ‘k eing imfolded by using collage and assemblage， the students were able to more diverse materials properly. Their ay to utilize the materials was Est‘râ llized in a way to makè a good use of ‘the unique characteristics of the materials and their skìll to handle them also became more flexible. Student 1 used various colors even for the same\" materials， and student 2 used a piece of cloth as a hair， whiεh was beyond\" common usage. Stùdent 3 impfoved the use of bond and actively utilized magazines. Student 4 tried to make his works particularly personal and unique. Second， the collage and assemblage techniques exerted an influence\" on their concept of space.\" Student 3 showed the biggest change in drawing a diagram， and Student 1， 2 and 4 made the most change in three-dimensional image. There were less changes in cross section‘