The utility model discloses a device for detecting deformation parameter behind strand, including the slogan banner chi, it has a slide to erect fixed mounting respectively at the both ends of slogan banner chi, is connected with the horizontal pole between the slide at both ends, the cover is equipped with a plurality of scales and a plurality of sliders indulged on the slogan banner chi, every indulge scale and slider all through respective draw -in groove suit on the slogan banner chi, it has the slide groove to open on the slide, and a horizontal pole groove has been left respectively at the horizontal pole both ends, and the horizontal pole groove at horizontal pole both ends is connected with the slide groove on the slide through a set of coupling assembling respectively. The utility model discloses a device among the deformation process, can realize that after strain roll spacing and drafts parameter once all detect behind the strand to back deformation parameter adjustment be can guide, each strand, rope stress are realized unanimously.