The utility model discloses a direct-current power transmission straight-line iron tower for a large-cross-section steel core aluminum alloy type stranded wire. Each of two types of towers comprises tower legs, tower body and a lead wire crosspiece, wherein the lead wire crosspiece is arranged on the tower body and extends from two sides of the tower body, and a lower plane of the lead wire crosspiece is perpendicular to the middle axis. A ground wire support is erected on the lead wire crosspiece and extends towards two sides, and upper and lower planes of an oblique portion of the ground wire support and the middle axis form included angles smaller than 90 degrees. The open crotch portion of the direct-current power transmission straight-line iron tower for the large-cross-section steel core aluminum alloy type stranded wire at the position of a public connecting leg is closed, and the anti-torque capacity ad rigidity of the iron power are improved under the condition that tower materials are slightly added. High-strength steel is applied to an iron tower main material and the crosspiece, stresses at the positions are large, or the positions mainly bear tensile force, the strength advantage of the high-strength steel can be fully played, the component number is decreased, a structure load transferring mode can be reasonable, and the advancement and the safety reliability of the iron tower structure can be effectively improved. In addition, the direct-current power transmission straight-line iron tower serves as a direct-current power transmission tower, and corridor resources can be effectively saved under the same-class voltage grade condition.