The Min-Delta urban agglomeration is experiencing serious problems with material metabolism as a result of urbanization. At the same time, the hazards associated with issues related to material metabolism and their diffusion effects become increasingly noticeable as the urban agglomeration metabolic network becomes more complicated. However, there is currently a lack of interpretation of the connotations of urban metabolic risk as well as reliable assessments of the shock and diffusion effects of metabolic risk. Therefore, this study quantifies the risk shocks of material metabolism in urban agglomeration by analyzing urban metabolic processes, then applies input-output analysis and structural path decomposition analysis to simulate the cascade diffusion pattern of metabolic risk, and finally quantifies the metabolic risk index and identifies metabolic risk hotspots using traditional risk assessment methods. The results indicate that the Min-Delta urban agglomeration experiences a material metabolic risk shock of about 700 Mt, which leads to a diffusion effect of over 1000 Mt, of which the metabolic risk of intra-city diffusion accounts for 80%, and is dominated by construction → other services (39-41 and 20-22 Mt) and construction → residential consumption (23-28 and 15-17 Mt) in Quanzhou and Zhangzhou, respectively. The metabolism risk index increased by 59% during the study period, in which the construction, manufacturing, and residential consumption in Quanzhou and construction in Zhangzhou contributed the largest share of 26%, 21%, 13%, and 12%, which are potential risk hotspots with risk levels of dangerous, dangerous, very high, and medium. The methodology proposed in this study establishes a quantitative framework for evaluating urban metabolic risk and diffusing consequences. The findings contribute to the diagnosis of urban ecosystem health and urban development transformation in the context of urbanization.