According to the exploration contract about polymetallic sulfides in the SWIR(Southwest Indian Ridge)signed by China with the International Seabed Authority,to delineate sulfide minerals and estimate resource quantity are urgent tasks.We independently developed our first coincident loop Transient Electromagnetic Method(TEM)device in 2010,and gained the TEM data for seafloor sulfide at South Atlantic Ridge 13.2°S in June 2011.In contrast with the widely applied CSEM(Marine controlled-source electromagnetic)method,whose goal is to explore hydrocarbons(oil/gas)of higher resistivity than seawater from 102to 103m below the sea floor,the TEM is for low resistivity minerals,and the target depth is from 0 to 100 m below the sea floor.Based on the development of complex sulfide geoelectrial models,this paper analyzed the TEM data obtained,proposing a new method for seafloor sulfide detection.We present the preliminary trial results,in the form of apparent resistivity sections for both half-space and full-space conditions.The results correspond well with the observations of the actual hydrothermal vent area,and the detection depth reached50–100m below the bed,which verified the capability of the equipment. According to the exploration contract about polymetallic sulfides in the SWIR (Southwest Indian Ridge) signed by China with the International Seabed Authority, to delineate sulfide minerals and estimate resource quantity are urgent tasks. We independently developed our first coincident loop Transient Electromagnetic Method (TEM) device in 2010, and gained the TEM data for seafloor sulfide at South Atlantic Ridge 13.2 ° S in June 2011. In contrast with the widely applied CSEM (Marine controlled-source electromagnetic) method, whose goal is to explore hydrocarbons (oil / gas) of higher resistivity than seawater from 102 to 103m below the sea floor, the TEM is for low resistivity minerals, and the target depth is from 0 to 100 m below the sea floor. Based on the development of complex sulfide geoelectrial models, this paper analyzed the We present the preliminary trial results, in the form of apparent resistivity sections for both half-spa ce and full-space conditions. The results correspond well with the observations of the actual hydrothermal vent area, and the detection depth reached 50-100m below the bed, which verified the capability of the equipment.