As an important part of the rapid transportation network，the construction of high-speed railway ( HSR) plays an important role in urban labor productivity．The supply of HSＲ services not only increases the marginal benefit of population agglomeration，but also helps to enhance the capability of integrated transportation．Firstly，this paper conducts a theoretical discussion about how HSR construction affects urban labor productivity，and then discusses the impact of heterogeneity of HSR service supply on labor productivity in different regions and industries through constructing a two-way fixed effect model.Finally，based on the perspective of population agglomeration and public transportation，an empirically study of the threshold effect of HSＲ service supply on urban labor productivity．The results show that the supply of HSＲ services has a positive and significant effect on urban labor productivity，particular in western region．The HSＲ service supply has the greatest impact on labor productivity of urban service industries，but which has no significant impact on agriculture．The test results of threshold effect show that the positive impact of HSＲ service supply on urban labor productivity will be better brought into play，when the urban population density exceeds the marginal threshold，and the number of public transport steam and electricity per 10000 people is within a certain range．
