The utility model provides a positive negative phase sequence of single loop transform angle -steel tower. It includes body of the tower, top layer ground wire cross arm, middle level wire cross arm, lower floor's wire cross arm, middle level wire cross arm is the T style of calligraphy, arranges the both sides cross arm from the perpendicular target circuit orientation of body of the tower, arranges supplementary cross arm on one side from the parallel target circuit orientation of body of the tower towards the large size side, lower floor's wire cross arm is the T style of calligraphy, arranges the both sides cross arm from the perpendicular target circuit orientation of body of the tower, arranges supplementary cross arm on one side from the parallel target circuit orientation of body of the tower towards the trumpet side. The utility model discloses a positive negative phase sequence of single loop transform problem is solved to a basic shaft tower, has avoided the single time adjacent tangent tower wire vertical state of string bias that dangles simultaneously.