Abstract: Production technology of hydrogen sulfide by using phosphogypsum as raw material was researched.Firstly,phosphogypsum was calcined into calcium sulfide.Then,calcium sulfide was acidulated and decomposed by carbon dioxide to produce hydrogen sulfide.Through the single factor analysis and orthogonal experimental design,optimum process parameters for hydrogen sulfide production from calcium sulfide were determined.Optimum process parameters were:reaction temperature was room temperature，stream velocity of CO<SUB>2</SUB>&nbsp; was 110±10 air bubbles/min,liquid-solid ratio was 3 mL/g,and reaction time was 3 h.Under these conditions sulfur conversion rate was 98% and sulfur content of the residue could go down to 1% below.