The inner diameter of shield tunnel segment has a significant effect on integral performance of tunnel structure. In this paper, the stateoftheart of the selection of inner diameter of shield tunnel segment in China and abroad is studied in terms of tunnel service life, tunnel construction clearance, track laying and technoeconomic benefit. The study results show that: 1) The tunnel construction clearance should be 5 300 mm so as to guarantee vibration reducing effect of track bed in special section. 2) The inner diameter of shield tunnel segment should be enlarged to more than 5 800 mm so as to guarantee the tunnel service life, provide space for secondary lining of tunnel and reduce maintaining cost obviously.