Design space optimization using design space adjustment and refinement is used to optimize a knuckle in the suspension system of an automobile. This approach is a new efficient method for large-scale topology optimization by virtue of two reasons. First, design space adjustment including design space expansion and reduction is suitable for large-scale problems. Second, the design space refinement can be done globally or locally where and when necessary and thus is very effective in obtaining a target resolution with much less number of elements. Compliance minimization for a knuckle is considered with a realistic working condition to show the effectiveness and superiority of the new approach.