本計畫旨在討論當生產活動會造成環境汙染時，地主國政府面對可能前來直接投資的跨國廠商時，應如何訂定最適環境稅。由於環境稅不可能對本國及跨國廠商有差別待遇，加上環境稅不能為負，這些都使得地主國政府在訂定環境稅時顯得特別困難。本計畫欲探討環境稅除了傳統的矯正汙染外部性扭曲之外，還會如何作為吸引或阻卻外人直接投資的政策工具。本計畫也擬進一步探討地主國的市場結構、廠商具有綠色企業社會責任、廠商考量從事污染防治等不同背景對地主國政府最適環境稅的影響，也擬探討地主國政府是否有更適當的環境政策工具。 ;The purpose of this project is to analyze the optimal environmental tax of a host country when facing a multinational firm who may potentially invest in the host country. Due to the non-discriminatory and non-negative properties of the environmental tax, it is difficult for the host government to decide the optimal environmental tax level. In this project, the objective of the environmental tax is not only to correct the pollution externality but also serve as an instrument to attract or deter foreign direct investment. In addition, how do the host market structure, green corporate social responsibility, and pollution abatement affect host government’s optimal environmental tax will also be studied. Finally, other possible environmental policy instrument will be taken into account.