本文探討在土地供給非固定及地價具有抗跌性的情況下，應如何改革土地稅以符合租稅的效率及公平基本原則。由於筆者發現提高增值稅會增加超額稅負，但是提高地價稅反而會降低，平均地權的土地稅制違背租稅的效率與公平基本原則，故建議應提高地價稅收回公共設施成本並將增值稅負調整至與綜所稅負一致才公平。加上，比例稅可克服實價認定困難，且其產生的行政效率遠大於累進稅量能課稅的益處，故乃建議增值稅改按實際增值比例稅課徵，並將稅率降至與綜所稅平均稅負一致。基此，最後筆者建議當前土地稅改革不宜仍遵循平均地權的土地稅制主張，即地價稅要輕增值稅要重，而應改朝地價稅要重增值稅要輕的逆方向進行改革。

The concept of constant supply of land in the economic literature being shown wrong, this paper uses new concept of nonconstant supply of land instead to investiagte the efficiency and the equity of land taxes. The author finds that an increase in the land value tax will decrease the excess burden and enhance the equity, but an increase in the land value increment tax will get the opposite results. However, the Republic of China have adopted the perverse policy, i.e., put heaviest taxes on land value increments but light taxation on land value. Therefore, reverse reforming current land taxation is suggested, namely, raising land value tax enough to get back the cost of the public goods and lowering the nominal land value increments tax rate to be same as that of the property income tax.