A power transmission iron tower three-dimensional virtual assembly method includes following steps: 1, discomposing a power transmission iron tower into a plurality of power components, classifying the power components after decomposing by adopting the object oriented technology according to state grid power equipment standards to obtain equipment attribute information of the components, and then identifying the power components to obtain equipment identification information; 2, correlating the equipment attribute information with the equipment identification information of the power components, and creating a three-dimensional component type power equipment model by adopting the three-dimensional modeling technology to obtain a three-dimensional power equipment component model database; 3, establishing a power transmission iron tower assembly relationship data model according to spatial configuration and assembly relationship among the power components; and 4, performing virtual assembly to the three-dimensional component type power equipment model according to the established power transmission iron tower assembly relationship data model to obtain a complete power transmission iron tower three-dimensional model.