Under the background of new urbanization, the impact of Lanzhou—Zhongchuan intercity railway construction on developing trend of regional economy was studied at the macro-level. Based on the analysis of the causal relationship among social economy, employment population, transportation and other related factors, a system dynamics model of the impact of intercity railway investment on Lanzhou economy trend was established. Through collecting data, the subsystem parameters of the model were de⁃ termined, and the linear analysis on GDP and investment in fixed assets was put forward by using SPSS software. The forecast of the regional economy development trend of Lanzhou was made and the policy scene adjustment simulation was carried out on the basis of the forecast results. Considering the invest⁃ ment in the intercity railway from Lanzhou to Zhongchuan is a short-term unsustainable project, the re⁃ sults show that although the increase of railway investment ratio has played a certain role in promoting the regional economy, its effect is limited and insignificant. In the future investment and construction, the long-term sustainable transport investment projects should be considered, so it can play a good role in promoting the regional economy developing.