This research examines the effects of urban rail transit (URT) on city growth measured by the increases in population, gross domestic product (GDP) and employment rate. Forty cities which have URT systems by the end of 2019 in China are taken as investigated samples. Research data related to URT extent, population, GDP, employment rate and five types of control variables which are individual, people's living, economic, science and education, and infrastructure are utilized and their applicability is verified. Panel data models are applied to analyze the effect of URT on city growth, and the robustness of the model estimation results is assessed. The study further analyzes the heterogeneity in the effects of URT systems on cities with different economic development levels. The estimated results indicate that the opening and expansion of URT have a positive effect on the population of the city. URT promotes the development of the urban economy and increases employment opportunities. Nevertheless, because of population migration, URT has little effect on the employment rate. In addition, the positive effect of URT on urban growth is most obvious for cities with a relatively high level of economic development.