The purpose of this study was to examine in which way teaching intervention by mothers who have children with downs syndrome would be affected by their own expectation disposition in quantity and quality during the course of problem solving through mother-child interaction and in which way the wooden pyramid problem-solving task of the children would be influenced by the same. And it\'s additionally intended to explore the relationship of the expectation disposition of the mothers to their own scaffolded instruction and their children\'s problem-solving learning. The subjects in this study were six selected children with downs syndrome and their mothers. The children who included three young boys and three girls were six years old in American age. The mother-child problem-solving interaction was videotaped, and qualitative and quantitative analyses were conducted to find out the quality and quantity of teaching intervention by the mothers, the degree of their contingent and non-contingent intervention, and whether the children resolved the given problem successfully or not. As a result, it\'s found that the mothers who had more positive expectation disposition relied more on contingent intervention that regulated the quality and quantity of intervention based on the success or failure of child\'s problem solving, and that their children produced better learning outcome than the children of the mothers who had more negative expectation disposition. In addition, there appeared a two-way interrelationship between the scaffolded instruction variable of the mothers and their children\'s problem-solving learning variable.