The invention discloses a calibrating tool and method for spacing among rotary-expanding rollers. The tool comprises a mould base, an elastic part, a slide block mechanism and a lifting ruler, whereina slide block mounting hole and a lifting hole are separately formed in the two sides of the mould base; the elastic part is arranged in the corresponding slide block mounting hole; one end of the slide block mechanism is limited in the corresponding slide block mounting hole, and the other end of the slide block mechanism is positioned outside the slide block mounting hole and abuts against thecorresponding roller; the slide block mechanism comprises a variable-diameter section; the bottom end of the lifting hole communicates with the corresponding slide block mounting hole; and the liftingruler is positioned in the corresponding lifting hole, and the bottom end of the lifting ruler abuts against the variable-diameter section, and the lifting ruler is driven by the variable-diameter section to lift. According to the calibrating tool and method for spacing among rotary-expanding rollers disclosed by the invention, the slide block mechanism moves along with the roller, so that the lifting ruler lifts along with action of the slide block mechanism; and readings of the lifting ruler are observed, so that the practical position of the roller can be obtained; and the roller spacing is calibrated, so that consumption of labor power is reduced, and calibrating precision can be improved.