Abstract: Based on the observation of the agglomeration of labor, capital and technological factors, this paper makes a quantitative assessment of the impact of high-speed railway operating on the transformation and development of contractionary cities. The results show that the spatial distribution of China's shrinking cities shows the aggregation characteristics of "small communities", mainly concentrated in Northeast China, the Pearl River Delta and the Yangtze River Delta. The estimation results of the Multi-Phase DID model show that the HSR operating in four to five years promotes, to a certain extent, the return of population in shrinking cities, but this positive effect does not have sustained stability, and the high-speed railway operating is not conducive to the economic development of the shrinking cities. The results of further mechanism tests show that the high-speed rail operating has not effectively driven the labor concentration in these cities, but caused the diffusion of capital factors to a certain extent. Finally, three suggestions are put forward to promote the transformation and development of shrinking cities, including establishing the concept of smart development, attracting and gathering talents and promoting inter-regional cooperation.