The key technology for the tower erection construction is studied in ±500 kV double-circuit DC transmission lines project from right-bank station of Xiluodu to Guangdong. Based on the special type of tower and the topographical features along the lines, the modular scheme for tower assembly is recommended by the holding pole internal-suspended and external(internal)-bracing. In addition, the lifting construction technology for the tower crossarm is introduced, providing technical support and guidance for the project construction.