中文摘要：

通过建立一个混合双寡头市场竞争模型，借以考察在国家征收环境税的条件下，国有企业的私有化程度对污染物排放、社会福利以及环境税率的影响。研究表明：当国有企业的私有化程度较低时，继续私有化将会导致污染物排放的增加和社会福利的增加；当国有企业的私有化程度较高时，继续私有化将会导致污染物排放的降低和社会福利的下降；同时，环境税则随着国有企业私有化程度的提高，始终保持下降趋势。

英文摘要：

This paper builds a mixed duopoly competition model to probe into the impact of privatization of state -owned enterprises on pollution emission, social welfare and environmental tax rate in the circumstance that the government imposes environmental taxes. The studies indicate that continuing privatization leads to an increase of pollutant emission and social welfare when the privatization level of state - owned enterprises is lower, while it will lead to a reduction of pollution emission and social welfare when the privatization level is higher. Furthermore, the environment tax rate will constantly drop when the extent of state -owned enterprise privatization increases.