The operation process of supply chain purchase financing is analyzed. A Stackelberg game is used to model the financing decisions. Firstly, the game equilibrium is analyzed. Then the effect of supply chain purchases financing to the supply chain is considered. The results show that, when the initial budget of the supplier is relatively small, supply chain financing can greatly improve the supply chain performance. The higher the wholesale price and salvage value are, the more the value of the supply chain financing is. The bank can get more profits by supporting the supplier with purchaseorder financing in the low risk market scenarios. The results show that the supply chain purchase financing is a win-win mechanism.