为了落实苏州建设规划的批复意见，对苏州市线网中的3、8号线是否要形成独立环线进行研究。通过总结苏州城市特征并借鉴国内外环线设置经验，对3、8号线设置独立环线的必要性和可能性进行定性和定量分析。通过对工程方案研究和客流测试对比，认为： 独立环线方案必要性不足；从工程实施上，仅具备构建勺型环线的土建条件，但工程投资大，有较大的工程浪费和社会风险，可实施性差。研究认为苏州这种水乡、多中心不均衡发展的城市更适合采用“组合环线+棋盘式”线网方案。

The independent loop line consisting of Line 3 and Line 8 of Suzhou urban rail transit system is studied, in order to implement the approved Suzhou urban rail transit construction plan. Qualitative and quantitative analysis is made on the necessity and possibility of the independent loop line by summarizing the layout characteristics of Suzhou city and drawing lessons from loop lines at home and abroad. Function analysis and comparison of passenger flow prediction indicate that there is lack of necessity in the independent loop line. Reserving a loop line of spoon type is feasible in civil construction, but the investment is huge, which will lead to great waste and social risks. The results suggest that “combined loop line + chessboard” network is more suitable for Suzhou city, a region with multicenters and unbalanced development.