The gates in port engineering are mostly large-span spatial structures due to functional requirements and shape limitations.As a type of large-span spatial structure,the spatial grid structure is widely used in the field of building structures due to its advantages such as large-span,light weight,good stability,fast construction,and beautiful appearance.Based on the actual engineering case,3D3S softwareis used to analyze the deflection,stress ratio and stability of steel structure grid roof,and the stress characteristics and structural design of grid structure applied to gate roof are expounded.The results show that the space grid structure has a high degree of safety,and the engineering design can meet the requirements of the specifications.The research results can provide a basis for further evaluating the reliability of such structures and similar engineering designs.