As an important organic intermediate of chemical industry,ethyl mercaptan is widely used inmedicine,industry,agriculture and other fields. For the solid acid catalyst for the synthesis of ethyl mer-captan by catalytic addition of ethylene and hydrogen sulfide,the properties,modification methods andthe mechanism of ethylene sulfidation reaction were discussed. The analysis indicates that the acid sitesare the active center of ethylene sulfidation to form ethyl mercaptan. The balance between the strongacid site concentration and weak acid site concentration determines the stability of solid acid catalyst.For modified alumina and metal sulfide catalysts,the interaction between the modified metal and thesupport is an important factor affecting the reaction activity.