Abstract: Paying corporate income tax is an obligation that all enterprises must undertake. The tax burden is a cost that all businesses cannot afford to ignore. But the tax act has led to a tax shield for businesses with financing. It could offset some of the taxes that should be paid by the capital-raising companies. So, to target to optimize supply chain enterprises in the financial system, it embodies in the supply chain enterprises have financing leverage risk and cost and tax shield effect in the process of weighing, and combines with different ways of financing interest cash situation analysis, so that more accurate and practical business decision-making has been done.Research is based on trade credit financing pattern, introducing the tax shield effect, and establishes a trade credit model with tax shield in a two-stage supply chain composed of a single core supplier and a single dealer. The research studies supply chain dealers' quantity strategy with financing needs are and core suppliers price strategy, discusses the value of explicit and implicit interest means on the enterprise supply chain. And the decision-making guidance is provided for the choice of the means of payment in the trade credit.Through the Stackbelberg game and optimization and comparative analysis, the best order decision of the distributor and the best price decision of the supplier are found, and further according to the way of interest on cash or a pre-determined recessive and dominant plan breath way of financing demand point, we put on the supply chain enterprise respectively in four kinds of situations. The comparison and analysis of the profit of enterprise target in different situation is analyzed, and the decision in the highest profit situation is the optimal decision choice of the enterprise.Through the comparative analysis, it is found that when dealers need financing after the quantity of goods is determined, if tax on the interest deduction ceiling is lower than the similar bank loan rate in the same period, implicit interest settlement is far more valuable to dealers; When dealers need financing before ordering and credit line is lower than a critical value under explicit way, dealers are motivated to prefer radical ordering strategy with the way of implicit interest. At the same time, the cost of tax and purchasing and expected earning is a tradeoff for dealers. Different ways of interest with a special turn are chosen when the order quantity is different. When suppliers need financing before ordering, if production cost balance under two way of interest settlement is lower than a critical value, implicit interest settlement is more valuable to suppliers; When suppliers need financing after ordering, suppliers should choose the better way of interest settlement combing with pricing strategy.Finally, an example is used to discuss the distributed photovoltaic power plant and power grid generation in the process of trade credit payment delay occurs, profits and the decision variables of the power plant and power grid and the decision variables and the relationship between important parameters. The conclusion of this paper is proved by numerical analysis. Our research will help the analysis of enterprise decisions in other financing modes of supply chain finance. The disadvantages of ignoring the tax factors of traditional supply chain financial models are remedied. It not only makes the financing in the supply chain enterprise decision-making more accurate and more guiding significance, but also provides strong evidence for financing on the supply chain enterprise's capital structure adjustment and the establishment of financial decisions. Because the research is based on the fact that the enterprise income tax is taken as the breakthrough point in many types of taxes, so for other relevant tax and financial system of supply chain optimization and decision-making, research has inspired lead role. Other relevant research can be based on this model and follow the research idea of this paper.

Key words: trade credit, tax shield effect, operational strategy, the way of interest settlement