The impact of high-speed rail (HSR) on the development of peripheral cities remains debated. Based on China data from 2008 to 2017, this article constructs an HSR operation network (HSRON) model to study the impact of network position (NP) on service industry agglomeration (SIA) by employing complex network analysis and panel regression methods. The results reveal that: (1) the improvement in NP might inhibit SIA in peripheral regions, especially in the producer and consumer services. (2) Compared with cities within one-hour temporal distance of core cities, those beyond such distance experience more losses. Besides this, cities with populations of between 0.78 ~ 1.56 million suffer more losses than other cities. In addition, a city will lose more if its nearby core city has a larger market potential. But when the distance, population, and nearby core city’s market potential exceed a certain level, the loss becomes nonsignificant. (3) The loss is due to urban expansion and investment reduction.