决策树是在已知各种情况发生概率的基础上，通过构成决策树来求取净现值的期望值大于等于零的概率，评价项目风险，判断其可行性的决策分析方法。代码通过汽车性能案例分别建立决策树和回归树进行预测。-Decision tree is based on the known probability of occurrence of various situations, through the decision tree to obtain the expected value of net present value is greater than or equal to zero probability,　uation of project risk, determine the feasibility of decision analysis method. The codes are used to build the decision tree and the regression tree to predict the vehicle performance.