Abstract: Outdoor termination is an indispensable accessory for the connection between high voltage and ultra-high voltage transmission cable and overhead line. Its installation environment is complex and the termination withstand a variety of external loads. In the design process of outdoor termination, it is necessary to fully consider whether its mechanical strength meets the requirements under various extreme loads. Through the analysis of the outgoing wire tension, wind load, earthquake force and short-circuit electrodynamic force under outdoor termination, calculate the deformation and stress of outdoor termination under the combined action of various external loads with simulation software, check the mechanical strength of bolt connecting termination bushing and base flange, base flange and support insulator.