介绍轨道交通线网合理规模的含义，以世界城市轨道交通较为成熟的东京、伦敦、巴黎、纽约、新加坡、上海、北京等城市为案例，总结其轨道交通发展指标。结合天津市的实际情况，采用交通出行需求分析法对天津市中心城市轨道交通的线网规模进行匡算；同时参照国内外同类城市轨道交通线网规模技术指标，从轨道交通线网面积密度和轨道交通线网人口密度两个方面，对服务水平进行类比分析，提出天津市中心城市轨道交通线网的规模。通过对比分析匡算结果，最终得出天津市中心城市轨道交通2020年线网合理规模为474～526 km，2040年线网合理规模为775～850 km。

It takes the cities that urban rail transit is relatively mature in the world as a case, summarizes the urban rail transit development indicators. By linking with the Tianjin city realistic situation, The methods of traffic demand analysis are proposed. With reference to domestic and foreign similar technical indicators of urban rail transit network scale, the analogy analysis was carried out on the service level in the area density and population density of the rail transit network two aspects to estimate the scale of t rail transit network of Tianjin .A rational scale length of Tianjin urban rapid rail network plan in the near future and in the considerable future is obtained by comprehensively comparing and analyzing those estimated scales.