A new process of ring-roller spinning was proposed, which has a plane compressive shear stress state where the stress triaxiality in the deformation zone was less than the fracture cut-off value，namely, η＜-1/3, and the influence laws of this stress state on the plastic deformation during the ring-roller spinning process for tube was investigated. Then, the stress state distribution in the deformation zone and the microstructure evolution characteristics based on this stress state were verified by a combination of finite element and material characterization method, and the wall-reducing processing of 304 austenitic stainless steel seamless  tube with the size of 57 mm×3 mm was carried out by a rotary ring-roller spinning machine of independent design and processing. Furthermore, the stainless steel seamless tube with the minimum wall thickness of 0.35 mm were obtained after five passes of continuous ring-rolling spinning process without intermediate annealing, and the morphological characteristics, material properties and microstructure of the processed tube specimens were characterized. The results show that after forming the wall thickness uniformity of tube is good, the volume fraction of martensite phase increases to 35%, and reaches the peak value. When the cumulative deformation amount reaches 1.8 mm, the grain size reaches 200 nm and remains stable. The subsequent plastic deformation process is achieved through grain tensile fracture and grain boundary strengthening plasticizing effects.