The invention discloses a rolling and forming method for a 0Cr25Ni20Mo2 stainless steel thin-wall ring, aiming to roll and form the thin-wall ring with high forming size precision and good tissue and performance. The invention has the technical scheme that the method comprises the following steps of: firstly, sheathing a 0Cr25Ni20Mo2 stainless steel pre-rolled blank which is heated to deformation temperature and a preheated follow-up die sleeve into a ring rolling machine, sheathing the follow-up die sleeve into the pre-rolled blank, and positioning the two workpieces by using a home roll, a core roll, a snubber roll and upper and lower cone rolls of the ring rolling machine; then starting the ring rolling machine, and enabling core roll to make the feed movement along the radial direction towards the direction of the home roll and roll the pre-rolled blank together with the home roll by a rolling force of 150KN-2,900KN under the support of the follow-up die sleeve to make the pre-rolled blank broadened along the radial direction at the speed of 7mm/s-13mm/s so that the wall thickness of the pre-rolled blank is gradually reduced; and rolling the pre-rolled blank into the thin-wall ring after the deformation of the pre-rolled blank reaches 40-60 percent. The minimum wall thickness value of the 0Cr25Ni20Mo2 stainless steel thin-wall ring rolled and formed by the method is 25mm, and the maximum value of height-thickness ratio is 25mm. The ring is mainly used for a revolving body part used in oil gas field and the like.