Abstract: Using a 5-mm-thick hot-rolled plate as the starting material, specimens were cold-rolled to various reductions (60%, 80%, 90%, 94% and 96%) and subsequently subjected to high-temperature tensile testing at 800 ℃ and 1×10^-2 s^-1. Scanning electron microscopy, electron backscatter diffraction, and transmission electron microscopy were employed to characterize the microstructure-property evolution, aiming to clarify the effect of cold rolling reduction on the superplasticity of Fe-35Mn-8Al-0.3C low-density steel. The high-temperature tensile results show that all cold-rolled samples (with reductions of 60%-96%) exhibit elongations exceeding 300% under the tested conditions, demonstrating typical superplastic behavior. With increasing reduction, the elongation gradually rises from 341% for the 60% cold-rolled sheet to a maximum of 612.5% for the 94% cold-rolled sheet. Microstructural characterization reveals that Mn redistribution and dynamic recrystallization occur during high-temperature tensile deformation, transforming the initial cold-rolled α+γ dual-phase banded structure into an equiaxed dual-phase structure consisting of Mn-rich β-Mn and γ phases in an interlocked configuration. As the cold rolling reduction increases, the fraction of dynamic recrystallization after high-temperature tension rises from 79.6% to 99%, while the volume fractions of β-Mn and γ phases remain comparable and the grain size stabilizes at 1-2 μm, indicating that the final microstructure is largely independent of the initial reduction. After superplastic deformation, the hard β-Mn phase exhibits a fully recrystallized structure, whereas the soft γ phase retains a high density of dislocations. Based on these findings, a pre-deformation process with a cold rolling reduction of 90%-94% is identified as capable of yielding approximately 600% elongation, and the superplastic deformation mechanism of the low-density steel is proposed to be jointly governed by dislocation slip in the γ phase and grain boundary/phase boundary sliding.