This paper elaborates a Markowitz -S harpe Model by combining Markowitz Model and Sharpe' s Capital Asset Pricing Mode on the basis of Mean Variance.In view of the capital bud geting features and the optimizatio n model of Capital budgeting under certainty conditions,The authors infe rred the Capital Budgeting Optimiza tion Model under uncertainty condition o n the basis of Net Present Value -Abso lute Dispersion.