As an important method to expand living and development space,land reclamation is widely practiced in many coastal countries in the world.The main engineering content of land reclamation includes the dyke and reclamation,and the closure design has great influences on the construction,safety and cost of the project.This paper uses a mega project as an example to discuss how to reasonably determine the closure position,dividing regions,hydraulic calculations,protecting closure,construction security,economical efficiency,etc.,and summarizes the key points and standardized process of the closure design.