he performance of the interval design speed of urban rail transit lines is the basis for the efficiency of transportation organization and operational economics.The concept of speed efficiency was introduced based on the train's interval running speed,so as to measure the efficiency of the interval running speed.By analyzing the impacts of factors such as station spacing,interval design speed,and train performance on the interval running speed and speed efficiency,this paper drew the following conclusion:There is an optimal match between station spacing and interval design speed.Specifically,when the station spacing is less than 1.3 km,1.3~1.5 km,1.5~3.9 km,3.9~6.6 km,and more than 6.6 km,the recommended interval design speeds are 80 km/h,100 km/h,120 km/h,140 km/h,and 160 km/h,respectively.Moreover,when the station spacing is less than 4 km,the train's interval running speed increases and then decreases as the interval design speed increases,while the speed efficiency is negatively correlated with the interval design speed,and the rate of change gradually decreases.Finally,based on the theoretical calculation formula for speed efficiency,the range of interval running speed and speed efficiency corresponding to different interval design speeds and station spacing is obtained,which can be used as a reference for the construction and operation of rail transit lines and the revision of technical standards in the future.