In EPC engineering general contracting projects, the transmission of interface risks between the "design procurement construction" stages can have significant adverse effects on project progress, cost, and quality. Scientific implementation of interface risk control is the key to ensuring the smooth progress of the project. The article systematically sorts out the transmission path and main characteristics of interface risks in each link of "design procurement construction", identifies core risk factors such as information asymmetry and poor process connection, and proposes targeted control measures based on this. Research has shown that construction units can effectively reduce the probability of risk transmission and improve the overall project management level by optimizing interface communication mechanisms and building risk warning systems.