Abstract: Themagneticfielddesigndirectlyinfluencesthestabilityandtheinorbitlifeofthedischargechamber.Aimingatthecomplexityofthe30cmxenonionthrustermagneticfielddesigninvarietyofoperatingmodes，themagneticcircuitcharacteristicswasanalyzedduringtheconversionbetweentheelectromagnetandpermanentmagnet.Andthekeyparametersofthepermanentmagnetwereoptimized.Themagneticcircuitmodelofthe30cmxenonionthrusterwasestablished，combinedwiththefiniteelementmethod，theeffectivenessandfeasiblityofthismethodwasvalidatedbycomparedwiththejobsitedata.Basedonthismodel，thekeyparametersofthepermanentmagnetwhichcouldproducerequestedmagneticinductionintensitywereobtained.Thenthekeyparametersofthepermanentmagnetwereoptimizedbyusingmultiobjectiveparticleswarmoptimization(MPSO)algorithm，withthegoaloftheminimumanodeshockvoltage，acceleratorgridcurrent，deceleratorgridcurrentandmagneticcircuitsystemweightsystem，andtherelevantoptimalresultofmagneticcircuitconfigurationfor30cmxenonionthrusterwasobserved．Aboveresearchwillcertainlyprovideamethodforthedesignandoptimizationoftheionthruster.

Key words: ionthruster, electromagnet, permanentmagnet, magneticcircuitmodel, optimizationdesign