Considering two kinds of the products,the one is the end of the season unsold,the other is old one,the paper analyzes the basic decision model of supply chain under carbon tax circumstances.Then,for the end of the season unsold products,the paper builts a buyback contract model between manufacturer and retailer to optimize the wholesale price and buyback fee by the optimal buyback rate.For the old products,considering the subsidies policies of the used recycling and technology upgrading,the paper explores o...