Abstract: Withthedevelopmentofhighpowerandminiaturizationinsatellitepayload,accuratesimulationandthresholdanalysisformultipactorin   complexcomponentbecomesbottleneckproblem.Basedontheparticleincelltechnologyandthesecondaryelectronemissiontheory,athreedimensionalsimulationmethodformultipactorwaspresented.Thenumericalalgorithmwasselfconsistentsincetheinteractionbetweenelectromagneticfieldsandparticleswasproperlymodeled.Thegenerationofmultipactoris   visualized,  sothat adeepinsightintothephysicalmechanismsofthiseffectwasgained.Inordertovalidatethemethod,multipactionintheimpedancetransformerwasstudied.Byanalyzingtheevolutionoftheelectronnumbersobtainedbyourmethod,multipactorthresholdsofthesecomponentswereestimatedandthemostsensitivepositionswheremultipactoroccurswerevisualized.Theresultsshowgoodagreementwiththeexperimentalresultsandthesimulationerrorislessthan1.2dB.

Key words: space, highpower, multipactor, numericalsimulation, passivecomponent