Greenhouse gas emissions have serious impacts on the natural environment． Considering emission trading and investment of emission reduction technology，models were presented for a two-stage supply chain to analyze the optimal investment decisions and incentive mechanism design under asymmetric consumer preference information． The results indicate that information sharing can be realized by an incentive mechanism，but such a mechanism can’t ensure the optimal performance of the whole system． The manufacture’s profit will be less due to the lack of accurate information about consumer preference，while the retailer with private information may gain an above-reservation profit． There is appositive correlation between the optimal percentage of emission reduction and a consumer’s low-carbon preference． Meanwhile，the government can promote investment in emission-reduction technologies and achieve its emission reduction target by controlling emission trading prices and providing technology investment subsidies．