Under the targets of “Carbon Peak” and “Carbon neutral”, our goal in this paper is to extend Tobin Q theory under carbon emission reduction (henceforth, CER) to develop an asset equilibrium pricing when a firm has agency conflicts. By bringing CER into corporate asset equilibrium pricing, the results of the analysis show that: 1) CER reduces bad effects of social environment concern on capital stock to increase future consumption and decrease volatility of future marginal utility. However, the cost of CER leads to underinvestment of capital and reduces future consumption. Therefore, the firm carries out CER and needs to find optimal CER to minimum bad effects. 2) CER has a significant effect on corporate asset equilibrium pricing. We show that CER leads to underinvestment of capital and increases risk-free rate. As for expected return, we demonstrate that CER increases dividend yields and decreases equilibrium risk premium. And CER increases Tobin Q and reduces controlling shareholders’ agency cost. 3) Volatility of capital stock, risk averse and social environment concern increase CER. We also show that controlling shareholder’s cash-flow rights, investor protection and the margin cost of CER reduce CER.