轨道交通成网运行背景下，简单的线路形态和交路组织已难以满足多样化的乘客出行需求；为应对复杂方向上客流出行带来的交通供给与需求不匹配问题，文中借鉴既有对Y型线的研究，提出了一般树型线的轨道交通线路形式，并参照实际运营的线路案例将其分为直径型和半径型两种类型。首先，设计了一般树型线的线路拓扑形态，并以发车频率为决策变量，以乘客出行时间与企业运营成本最小为目标函数，考虑乘客在不同交路列车之间的分配问题，构建了一般树型线条件下的列车开行方案优化模型；然后设计了带精英策略的非支配排序遗传算法（NSGA-Ⅱ）进行求解，并以巴黎RER A线为例对模型与算法进行了验证；最后，将优化方案与分线运营的方案进行了对比。结果表明：算法可求得开行方案的帕累托前沿解，乘客出行时间与企业运营成本呈现明显的负相关性；得到的优化方案与分线方案相比，在乘客出行时间和企业运营成本方面都有显著的减少，可使乘客候车时间减少1.76%～12.90%、乘客换乘时间减少33.63%～34.98%，列车总走行里程减少7.69%～21.67%，上线车底数减少9～19列。

In the background of rail transit network operation, the simple line and routing forms can no longer meet the diverse passenger travel demand. Therefore, in order to cope with the mismatch between traffic supply and demand brought about by passenger trips in complex directions, the paper proposed a rail transit line form of general Tree-type line based on the existing research on Y-type lines, and it was divided into diameter type and radius type with reference to the actual operating line cases. Firstly, the paper designed a line topology form of Tree-type line and established a multi-routing planning optimization model for Tree-type line by considering the distribution of passengers among different trains and taking the departure frequency as the decision variable and the passenger travel time and minimum operating cost as the target function. Then it designed and solved the non-dominant ranking genetic algorithm (NSGA-Ⅱ) with the elite strategy. The model and algorithm were validated using the RER A line in Paris as an example. Finally, the optimization scheme was compared with the split-line scheme. The results show that: the algorithm can find the Pareto frontier solutions of the train planning, and the travel time of passengers and the operation cost of enterprises show a significant negative correlation; the obtained optimization scheme has a significant reduction in the travel time of passengers and the operation cost of enterprises compared with the split-line scheme. It reduces the waiting time of passengers by 1.76% to 12.90%, the transfer time of passengers by 33.63% to 34.98%, the total running kilometres of trains by 7.69% to 21.67%, and the the number of trains on the line by 9 to 19.