Abstract: InordertorealizethelongtermsteadydriftofTianqinMission′sorbitalconfigurationandmeetstabilityindex,initialoptimuminstantaneousorbitalelementsweresearchedbytheoptimizationalgorithm.Firstly，orbitaldynamicsmodelconsideringperturbationwassetup.Secondly,theorbitalconfigurationofequilateraltriangledriftedforlong-periodbytheorbitalelements′varietywasresearchedandtheorbitalelementsleadingtotheorbitalconfigurationofequilateraltriangledriftedinalongperiodweremadeasparameterstobeoptimized.Particleswarmintelligentoptimizationalgorithm（PSO）wasappliedtooptimizeparametersselectedforoptimization.Finally,thesimulationresultsshowthatthearmlengthchangeslessthan1500km，thebreathanglechangeslessthan1.5degreesandthevelocityofthearmlengthvarietychangeslessthan10m/sinnaturaldriftingoffouryearswithoutorbitalmaneuver.Theresultsmeettheinitialindicatorsoftheorbitalconfiguration.

Key words: TianqinMission, orbitalconfiguration, longtermdrift, stability, particleswarmoptimization