In highly urbanized areas, erecting ± 800 kV polar wires and ground electrode wires on the same tower is the best choice to solve the shortage of transmission line corridors and scarcity of land resources. However, there are few researches on the electromagnetic environment of this type of tower at home and abroad. In this paper, the conventional calculation method is expanded to consider the shielding effect of ground electrode wires to the electromagnetic environment of polar wires. Taking the ±800 kV Dianxibei to Guangdong UHVDC Project as example, the audible noise, radio interference, total field strength above ground and ion current density under horizontally and vertically arranged modes of same tower hybrid transmission lines are discussed. The results show that the total electric field strength above ground of same tower hybrid transmissin lines is less than the DC line, and the transmission line corridors can be compressed about 44% by using the vertical arrangement of same tower hybrid transmissin lines.