Under the background that environmental tax has increasingly become the main means of environmental governance in various countries, it is particularly important to study the effect of environmental tax on reducing pollutants and then put forward suggestions for building a scientific and rational environmental tax system. The novelty of this paper is the investigation of the pollutant emission reduction effects of environmental taxes in Organization for Economic Cooperation and Development (OECD) countries and Chinese provinces at the same time, and further comparison of the pollutant emission reduction effects of environmental taxes in OECD and China under different environmental tax collection scales, industrial added value levels, and economic development conditions based on Auto-Regressive Distributed Lag Modelling Approach (ARDL). The data are derived from environmental taxes and pollutants of OECD countries from 1994 to 2016 and Chinese provinces from 2004 to 2016. The results show that from the overall regression results, environmental taxes really help to reduce pollutant emissions, both in OECD countries and China. From the grouping regression results, the OECD countries and Chinese inland provinces with small-scale or medium-level of environmental tax revenue and higher level of economic growth all show better emission reduction effects, while OECD countries with low industrial added value and Chinese inland provinces with high industrial added value have more significant effects on pollutant emission reduction via environmental taxes.