A construction method for installing underground pipes for high-tension cables uses a trough. The method includes the steps of forming an excavation trench by excavating the ground, installing the trough on the bottom of the excavation trench, pouring sand into the space section, placing the underground pipes on the sand, pouring again the sand onto the underground pipes, filling a gap formed between the trough and the excavation trench using sand and gravel, forming an upper protecting member on the trough, and performing surface treatment by using road pavement materials.