Real estate valuation theory indicates three principles of contributions: land contribution, building contribution, and joint contribution. Many researchers advocate the principle of land contribution because land is sustainable and without depreciation. According to valuation and economic theory, the principle of joint contribution conforms to the theoretic implication comparatively; therefore, it is worth exploring the debates between the principle of land contribution and the principle of joint contribution. Compared to the land price index of Ministry of the Interior, this paper tries to find a more reasonable allocation ratio and establish a land price index. Empirical evidences seem to indicate that the land price model based on the principle of joint contribution is better than is the model based on other principles. On the contrary, the trend of the land price index of the Ministry of the Interior is different from the housing price index because land quality is not controlled.