Carbon emission policies bring new challenges to the enterprise operation and supply chain management, making the decision of management more complicated. With a two-echelon supply chain consisting of one supplier and one manufacturer taken into consideration, the supply chain coordination with buyback contract under different carbon emission policies(carbon emissions tax, mandatory carbon emissions capacity, cap and trade) is researched and compared with the situation of no carbon constrain. The results show that, under different carbon policies, the buyback contract can coordinate the supply chain. The manufacture’s optimal order quantity gradually decreases under unconstrained condition, cap and trade, and mandatory carbon emissions capacity, while the buyback price offered by the supplier gradually increase.