Abstract: Aiming at the challenge that metastable austenitic stainless steel fails to achieve a coordinated balance between strength and toughness during low-temperature service, particularly that plastic deformation tends to degrade its impact properties, this work takes hot-rolled solid-solution (SS) metastable austenitic stainless steel as the research object. A 20% cold-rolled deformation (CR20) process was applied for microstructure regulation, to investigate the influence mechanism of plastic deformation on room-temperature mechanical properties and cryogenic toughness at -196 ℃. With the SS state as the control group, room-temperature tensile tests and -196 ℃ Charpy impact tests were conducted on CR20 specimens. The fracture morphology was observed by scanning electron microscopy (SEM); the phase composition, grain orientation and grain boundaries were analyzed via electron backscatter diffraction (EBSD); the evolution of dislocations, stacking faults and substructures was characterized through transmission electron microscopy (TEM). Accordingly, the differences in microstructure and mechanical properties between the two groups of specimens were systematically compared. The results show that the SS specimen possesses a uniform single-phase austenite microstructure. Whereas, as for CR20, strain-induced phase transformation takes place in the matrix, forming a γ+ε+α' three-phase composite structure. Meanwhile, high-density dislocations, dislocation cells, Lomer-Cottrell (LC) dislocation locks and massive stacking faults are formed inside the grains, building up a multi-level strengthening-toughening system. In terms of mechanical properties, compared with the SS state, the yield strength of the CR20 state increases from 313 MPa to 759 MPa, and the tensile strength rises from 727 MPa to 914 MPa, with the elongation after fracture maintained at 36%. Besides, its -196 ℃ impact energy reaches 65 J, satisfying the low-temperature service requirements of ship structures. Fracture mechanism analysis reveals that at -196 ℃, driven by stress-induced martensitic transformation, the fracture mode of the SS state shifts from ductile dimple fracture to a mixed dimple-quasi-cleavage mode. By contrast, the CR20 state synergistically retards crack propagation relying on retained austenite and stable phase interfaces. Its cryogenic fracture is dominated by quasi-cleavage morphology, and the extent of toughness deterioration is limited. In summary, 20% cold-rolled deformation effectively achieves favorable matching between high strength and cryogenic toughness of metastable stainless steel, which provides a theoretical reference for the deformation strengthening and toughening design of stainless steel for cryogenic engineering. Further optimization research can be carried out focusing on deformation gradient and heat treatment processes in follow-up work.