Abstract: Keynesian multiplier theory is only limite to describe aggregate of macro-economics, without the function of representing the quantitative relationship of structural change of investment and consumption. By using I-O technique, we extend Keynesian multiplier thoery from aggregate analysis to structural analysis, and set forth the second-stage I-O analytic method. The structural Keynesian multiplier analytical method includes two forms: 1. I-O table (second-stage I-O table);2. Mathematical model. By combination the quadrant of Ⅱ and m in orginal I-O table form the second-stage I-O table. Although the second-stage I-O table having the similar structural form and I-O model as theorginal I-O table, the economic contents expressed by model are totally different. We explain the concrete methods and steps to establish structural investment multiplier and consumption multiplier and the economic structural relationship reflected by the model and economic meanings of various coefficients. In addition, we also point out five aspects we should pay attention to when establish and apply the structural multiplier model.