The invention relates to a plug-in device for laying and fixing high-voltage large-section cable with adjustable position width, include a tab body, one side of the insertion piece body is an insertion part, The other side of the plug body is a mounting part, and the insertion part is used for inserting into the inside of the cable bracket. The mounting part is provided with a back-screw brace fixing hole. The cross-bar radial back-screw brace is pierced through the back-screw brace fixing hole for fixing the cross-bar of the scaffold, and the vertical-bar back-screw brace is matched with thecross-bar radial back-screw brace to form a radial I-frame. When a triangular scaffold is used for laying pulleys, circular small diameter pipe jacking tunnel, The problems of difficult walking, low working efficiency and difficulty in first aid escape of laying personnel in square large excavated cable culvert trench and compact caisson passage are solved, and the problem of lack of internal fulcrum of transverse I-shaped laying frame is solved. The radius type adjustable width laying is realized, and the device has the functions that the height is adjustable and through the width, walking ofa person is achieved..