The present invention discloses a fermentation production process for protein drugs, which is suitable for industrial fermentation production of sDSS1 protein drugs. The process comprises steps of : firstly employing a genetic engineering means to integrate an sDSS1 gene fragment into an expression plasmid, the integrated gene fragment comprising a purification tag; transforming and introducing the expression plasmid into a corresponding expression host, so as to construct recombinant engineering cells with a high level of expression; fermenting, expressing by induction, lysing, renaturing, and enzyme-digesting the recombinant engineering cells to obtain a crude pure protein; and continuing to conduct a series of fine purification steps to obtain a high-purity sDSS1 protein. The process is economical and effective.