The reduction of strain resistance caused by different compression variables and reverse strain of damping winding coupling material of hydro-generator set is studied, which is called Bauschinger effect, abbreviated as BE. The influence of different compression strain variables on damping winding connector BE was discussed. Through different compression strain compression and tension experiments, the optimal Baussinger extremum of damping winding copper connector was obtained. The results show that large compression variables have an effect on BE. With the increase of pre -deformation, the Bauschinger effect value changes. When the pre-deformation is 3%, the Bauschinger effect value reaches the extreme value. In addition, when the deformation is increased, the Bauschinger effect value ecreases, and 3% is the optimal shape variable, namely, the failure limit value of damping winding.