Abstract: Object:To obtain the high dense fermentation procedure of trehalose synthase (Tres) genetic engineering bacteria previously construct.Methods:Studied the influence of medium, pH, ferment mode for incubation and induction on the growth of recombinant genetic engineering bacterial and expression of target protein in a 10L auto control biostat fermentator, and explored the genetic stability of recombinant plasmid.Result:The high-density culture medium of trehalose synthase genetic engineering bacteria was 2YT+0.2%glucose, the optimum pH was 7.0, the ferment mode was fed-batch.After the recombinant genetic engineering bacterial strain cultured in 10L high-density fermentation, the density of bacteria reached 50.78g/L, the enzyme activity reached 3.197U/mL.The constructed recombinant plasmid was inherited steadily in host bacteria.Conclusion:The high-density fermentation condition of trehalose synthase genetic engineering bacteria was optimized.It laid a foundation of large-scale production of trehalose.