Abstract: Main space electric propulsion systems usually uses xenon as propellant.However,it’s limited by insufficient reserves and expensive price.As a new alternative propellant,iodine electric propulsion system has developed to the stage of engineering.By summarizing iodine hall thruster and iodine radio-frequency ion thruster,key technologies of iodine space electric propulsion are analyzed in the paper,including design for thruster and feed system,compatibility of plume and spacecraft and protection of test equipments to provide advices for optimization design of iodine space electric propulsion system.