Recombinant collagen is recognized as having broad application prospects in biomaterials and biomedicine. Type III collagen plays a critical role in maintaining human skin firmness and elasticity. To enhance its industrial production output and efficiency, high-yield engineered bacterial strains and efficient downstream purification processes for recombinant collagen must be established. The core functional region of the human Type III collagen mature peptide chain was selected based on the (Gly-X-Y) repeating unit, and its gene sequence was artificially optimized and synthesized. Three engineered Escherichia coli strains were constructed: pET28a-COL3A1/BL21(DE3) (without a solubility-enhancing tag), pGEX-4T-1-COL3A1/BL21(DE3) (fused with an N-terminal glutathione S-transferase (GST) tag), and pET-SUMO-COL3A1/BL21(DE3) (fused with an N-terminal small ubiquitinlike modifier (SUMO) tag). Soluble expression was achieved in all three strains, with soluble expression ratios of 14.09%, 19.22%, and 24.85%, respectively. The strain harboring the SUMO tag was selected for scale-up. Following 30 h of induction in a 3 L fermenter, the highest expression level reached was 1.02 g•L-1. After separation and purification, the recombinant collagen showed a purity exceeding by high-performance liquid chromatography and a molecular weight of 31.2 kDa by liquid chromatography-mass spectrometry. This study demonstrates that the SUMO tag markedly enhances the expression efficiency of recombinant collagen. A pilot-scale purification process was successfully established using the 3 L fermenter, providing a theoretical foundation for the scaled-up production and application of recombinant collagen.