A fixture comprising: an adsorbing assembly having a flexible disc made of soft material; a cover mounted on the flexible disc and having a top surface; a positioning pipe formed centrally on the top surface of the cover; a clamping assembly mounted in the cover of the adsorbing assembly and having a first clamping portion; a second clamping portion combined with the first clamping portion; an adjusting component clamped between the first clamping portion and the second clamping portion; characterized by the flexible disc having a pulling pole formed centrally on the flexible disc; the positioning pipe receiving the pulling pole of the flexible disc; and two protruding portions formed on the top surface of the cover and respectively located at two opposite sides of the positioning pipe; a handle connected to the positioning pipe of the cover and having two fastening portions respectively fastened with the two protruding portions of the cover; and a spindle mounted through the two fastening portions of the handle, the positioning pipe of the cover, and the pulling pole of the flexible disc, wherein when the handle is pressed, the spindle is moved upward relative to the cover by the handle to pull up the pulling pole of the flexible disc to make the flexible disc deformed elastically; the first clamping portion having a first placement region formed on an inner surface of the first clamping portion and having a first extending pole facing an inner side of the first clamping portion; and a second placement region formed on a bottom surface of the first clamping portion and having a second opening facing a top side of the first clamping portion and the direction of the second opening is perpendicular to the direction of the first extending pole; the adjusting component having a fastening plate vertically and movably mounted in the second placement region; a sliding pole transversely and moveably mounted through the fastening plate and the first clamping portion and facing the first placement region; and two compression springs respectively mounted in the first placement region and the second placement region, and respectively pushing the fastening plate and the sliding pole; a pivot clamping portion pivotally connected between the first clamping portion and the second clamping portion, and having a pushing groove formed on a bottom of the pivot clamping portion and abutting a top end of the fastening plate to make the pivot clamping portion fastened with the adjusting component. an adsorbing assembly having a flexible disc made of soft material; a cover mounted on the flexible disc and having a top surface; a positioning pipe formed centrally on the top surface of the cover; a clamping assembly mounted in the cover of the adsorbing assembly and having a first clamping portion; a second clamping portion combined with the first clamping portion; an adjusting component clamped between the first clamping portion and the second clamping portion; the positioning pipe receiving the pulling pole of the flexible disc; and two protruding portions formed on the top surface of the cover and respectively located at two opposite sides of the positioning pipe; a handle connected to the positioning pipe of the cover and having two fastening portions respectively fastened with the two protruding portions of the cover; and a spindle mounted through the two fastening portions of the handle, the positioning pipe of the cover, and the pulling pole of the flexible disc, wherein when the handle is pressed, the spindle is moved upward relative to the cover by the handle to pull up the pulling pole of the flexible disc to make the flexible disc deformed elastically; the first clamping portion having a first placement region formed on an inner surface of the first clamping portion and having a first extending pole facing an inner side of the first clamping portion; and a second placement region formed on a bottom surface of the first clamping portion and having a second opening facing a top side of the first clamping portion and the direction of the second opening is perpendicular to the direction of the first extending pole; a first placement region formed on an inner surface of the first clamping portion and having a first extending pole facing an inner side of the first clamping portion; and a second placement region formed on a bottom surface of the first clamping portion and having a second opening facing a top side of the first clamping portion and the direction of the second opening is the adjusting component having a fastening plate vertically and movably mounted in the second placement region; a sliding pole transversely and moveably mounted through the fastening plate and the first clamping portion and facing the first placement region; and two compression springs respectively mounted in the first placement region and the second placement region, and respectively pushing the fastening plate and the sliding pole; a fastening plate vertically and movably mounted in the second placement region; a sliding pole transversely and moveably mounted through the fastening plate and the first clamping portion and facing the first placement region; and two compression springs respectively mounted in the first placement region and the second placement region, and respectively pushing a pivot clamping portion pivotally connected between the first clamping portion and the second clamping portion, and having a pushing groove formed on a bottom of the pivot clamping portion and abutting a top end of the fastening plate to make the pivot clamping portion fastened with the adjusting component.