Abstract: The emergency ship lock, an integral hydraulic structure within the Changshanjiang hub series, serves crucial roles in flood discharge, lock maintenance, and specialized shipping operations. Despite its significance, both domestically and internationally, the hydraulic characteristics of the emergency ship lock remain understudied. This paper addresses this gap by first establishing a 1∶30 geometric ratio single physical model based on the emergency ship lock at a Changshanjiang shipping hub. Utilizing a combination of physical model test data and theoretical analysis, the study delves into the influencing factors and their respective degrees on the discharge capacity of the emergency ship lock. Additionally, the research explores the impact of varying gate heights on flow coefficients, culminating in the derivation of a recommended formula for the comprehensive flow coefficient of the emergency ship lock. The findings indicate that a significant upstream and downstream water level gap with minimal inundation results in a higher comprehensive flow coefficient, manifesting in a noticeable increase in flood discharge flow. However, as inundation severity rises, the incremental enhancement in the discharge capacity of the emergency ship lock gradually diminishes. The proposed formula for the comprehensive flow coefficient aligns closely with test values, showcasing minimal error. This formulation can serve as a valuable reference for the design of similar projects.