This paper analyzed effects Web-Based cooperation Learning have on improvement in Social Adaptability and problematic behavior, using Web-Based cooperation Learning system that is designed for Mental retardation children. Is Made Teaching Design according to students level, based on elementary school Bareunsaenghwal subject. Teaching and Learning program that is going with flash and PPT Embodied is. Designed to bulletin the evaluation data for cooperation studying after studying a part of the lesson. Verification of learning effect went with experimental group and comparison group consisted of groups of 8. Students studied the Internet web data and Teaching material paper and they took pencil test. As a result, point of post-inspection was higher than that of pre-inspection. Web-Based cooperation Learning is confirmed to be effective on Social Adaptability and problematic behavior improvement.