With the increase of environmental supervision in China, environmental protection investment has become an inevitable investment choice for polluting enterprises. However, whether environmental protection investment can bring value to the enterprise has always been a hot topic of debate. The paper takes the 2008-2016 China A-share heavy polluting industry listed companies as the research object, tests the correlation between environmental protection investment and market value. Using the Ohlson valuation model, it is found that environmental investment has a positive impact on the market value. Further, the paper examines two possible paths of environmental investment impact on market value, and the results show that environmental protection investment increases the earnings persistence, but has no significant impact on the cost of equity capital. Therefore, it is concluded that environmental protection investment is conducive to the increase of market value, and the mechanism of environmental protection investment affecting market value is to improve the sustainability of earnings.