The utility model provides a whole string of insulator of change strain insulator is with pull rod device of adjustable length, including the arm -tie, just the size is unanimous for total two of this arm -tie, the arm -tie is vertical shape's face -to -face setting, it uses interior arm -tie to be provided with a length adjustment between these two arm -ties, this length adjustment can perpendicular slip from top to bottom between two arm -ties with interior arm -tie, 6-8 arm -tie holes that are the perpendicular interval distribution of waiting are all seted up with length adjustment on one's body with the board of interior arm -tie to the arm -tie, connect to be connected with length adjustment the arm -tie with interior arm -tie with bolt and nut traversing arm -tie hole and fix, the bottom that length adjustment stretches out the arm -tie with the lower extreme of interior arm -tie, and this length adjustment is provided with one with the connection of the lower extreme of interior arm -tie and turns to the connecting plate, should turn to the connecting plate is connected with a hookup cardboard 6 again. The utility model discloses its is rational in infrastructure, the whole length and the pulling force angle can be adjusted of pull rod, and it is very convenient to adjust moreover, and the operating efficiency is high, the utility model discloses intensity is high, can not produce elastic expansion and warp, and is guaranteed in the security.