In the process of microbial solidification and stabilization of heavy metal contaminated soil, the rapid reaction rate and the inhibition of high concentration of salt ions on bacterial activity are the key problems that hinder the application of single stirring process. The solidification and stabilization tests of zinc-contaminated silt were carried out by using the single-stage microbial stirring method. In the tests, low-solubility gypsum (calcium sulfate dihydrate) was used as the calcium source for the microbially induced mineralization reaction, and the calcium salt content and zinc pollution concentration were adopted as the control variables to investigate the changes in soil strength, zinc ion leaching concentration and chemical forms. The results show that the solidification strength of 500 mg/kg zinc-contaminated silt is 77.3% higher than that of untreated zinc-contaminated silt. Meanwhile, the concentration of zinc ion leaching is 87.3% lower than that of untreated zinc-contaminated silt. After solidification and stabilization, the strength of zinc-contaminated silt dramatically improved and the migration of heavy metal zinc in soil significantly decreased. Calcium carbonate, zinc carbonate and basic zinc carbonate are formed in the solidified and stabilized zinc-contaminated silt, and carbonate crystals aggregate to form porous clusters. The single stirring method microbial mineralization treatment based on gypsum calcium source can effectively solidify and stabilize zinc-contaminated silt. This technique has potential application in solidifying/stabilizing zinc-contaminated silty soil site.