This work uses the event study method and EGARCH (Exponential Generalized Auto Regressive Conditional
Heteroskedasticity model) model to study the impact of environmental policies on the 36 listed Chinese oil and gas companies
during the period 2004–2017. The results show that although the overall impact of environmental policies on China's oil and gas
listed companies is negative, the negative impact of market-oriented environmental policies is smaller than command-and-control
environmental policies. Compared to the eastern region, the negative impact on oil and gas companies in the western and central
regions is smaller and the impact on larger companies is less negative than on smaller companies. This paper analyzes for the
first time the impact of environmental policies on the market value of China's oil and gas enterprises, provides guidelines for the
implementation of environmental policies in the oil and gas industry, and also provides guidelines for environmental policies on
oil and gas enterprises of different sizes and in different regions.