Abstract:This article studied the technology extracted by hydro-distillation of essential oil of hyssop，liquidsolid ratio，MgSO4concentration，the effect of extraction time on essential oil yield and quality，the best process condition was determined by orthogonal test，the factors of hyssopus officinalis essential oil yield effect was：Mg－SO4concentration＞ extraction time＞ratio of liquid to solid.Optimization of process conditions for the liquid to solid ratio 15 ∶1（mL/g），MgSO4concentration 10 g/L，extraction time 2 h，hyssopus officinalis essential oil yield was 0.688%.