The stagnation of unsold houses is recently aggravated due to domestic and overseas crisis of finance and real-sector economy and domestic housing construction is in serious difficulty. Thus, tax support is necessary for national housing construction. Due to the current tax exemption system of national housing, V.A.T. paid in the construction of national housing is not deducted. Namely, it is ascribed to consumer as it is reflected in the construction cost. This research intends to analyze the limit of V.A.T. tax exemption system, to present the necessity of applying zero rate and to calculate the scale of non-deduction of V.A.T. purchase tax amount for national housing by analyzing the construction site of apartment house of house constructor in order to analyze the effect of zero rate when it is applied on the basis of above ground. In the zero rate system, V.A.T. is not collected from the consumers like the present tax exemption system. However, the purchase tax amount borne in the construction of national housing is deducted totally. As purchase tax is deducted, constructor will promote supplying national housing thanks to the effect of solving financial difficulties and improving liquidity. Since the architecture cost and parceling-out price can be lowered due to the improved liquidity of constructor, the policy will actually help the people without house.