On the beginning of 2017, Indonesian government proposed a progressive property tax plan which will target land/property ownership and idle land. The purpose of this plan is to reduce land speculation that has increased the price of land and property significantly. Currently, Indonesia has never implement a progressive tax rate on its land and property ownership. Meanwhile, other countries such as Singapore has implemented this policy earlier for the same reason. This research aims to explore the legality of the tax plan through its conformity to the value embodied in Indonesian Agrarian Law and comparison of the tax plan to the similar tax system of other member of ASEAN countries such as Singapore has implemented. This reseach paper used a normative legal research. The outcome of the research is that progressive tax conformed to the values embodied in Indonesian Agrarian Law in which its emphasis is on equity for land use and distribution. On the comparison of progressive property rate between Indonesia and Singapore, it is found that both tax system shared the same object and purpose. Meanwhile, its difference is that the idle land tax is not at a progressive rate and progressive property tax scheme in both countries. Based on these findings, some advices have been proposed. First, Indonesian government should adopt similar tax scheme on the land/property ownership. Second, Indonesian government should clarify the requirement especially on the length of time for a land to be considered as an idle land.