In order to solve the problem of inner and outer diameter cracking defects that often occurred in the rolling process of aviation ring forgings, first of all, the rolling cracking morphology and the rolling process were observed, and it was found that the cracking was basically evenly distributed on the inner or outer diameter surface, the inner diameter cracking degree was greater than the outer diameter, the cracking basically started from the edges and extended in the axial and radial directions,  the cracking type was basically plastic cracking, and the proportion of cracking for small-sized thick-walled ring pieces was the highest. Then, the cracking mechanism of small-sized thick-walled ring pieces was studied in detail, and based on the rolling process characteristics of small-sized thick-walled ring pieces, a new rolling forming geometric model was established. Finally, an expression for the inner diameter rolling amount suitable for engineering applications was derived, which provides a quantitative basis for the inner diameter rolling amount to analyze and control the rolling cracking of small-sized thick-walled ring pieces, and also provides theoretical support for the formulation of rolling parameters.