Abstract: Water transfer projects generally have the characteristics of long lines and numbers of crossing buildings. People along the project have frequent social activities, and it is easy to cause social stability risks due to the spread of public emergency information. Based on the analysis on the factors affecting the social risk diffusion of water transfer engineering emergencies, this research constructs a system dynamics model for information diffusion of emergent social public events in water transfer engineering, including government subsystems, engineering department subsystems, media subsystems, and public subsystems. And we select a chemical leakage emergency public incident on a cross-river bridge to conduct simulation. The results show that the government and engineering departments have the greatest impact on the spread of risk event information. Reducing the level of incident risk and increasing the silence of each subsystem can reduce the negative impact of social emergencies and maintain social stability.