Excited-ground-state　transition　and　strand　slippage　of　RNA　play　key　roles　in　transcription　and　translation　of　central　dogma.　Due　to　limitation　of　current　experimental　techniques,　the　dynamic　structure　ensembles　of　RNA　remain　inadequately　understood.　Molecular　dynamics　simulations　offer　a　promising　complementary　approach,　whose　accuracy　depends　on　the　force　field.　Here,　we　develop　the　new　version　of　RNA　base-specific　force　field　(BSFF2)　to　address　underestimation　of　base　pairing　stability　and　artificial　backbone　conformations.　Extensive　evaluations　on　typical　RNA　systems　have　comprehensively　confirmed　the　accuracy　of　BSFF2.　Furthermore,　BSFF2　demonstrates　exceptional　efficiency　in　de　novo　folding　of　tetraloops　and　reproducing　base　pair　reshuffling　transition　between　RNA　excited　and　ground　states.　Then,　we　explored　the　RNA　strand　slippage　mechanism　with　BSFF2.　We　conducted　a　comprehensive　three-dimensional　structural　investigation　into　the　strand　slippage　of　the　most　complex　r(G4C2)9　repeat　element　and　presented　the　molecular　details　in　the　dynamic　transition　along　with　the　underlying　mechanism.　Our　results　of　capturing　the　strand　slippage,　excited-ground　transition,　de　novo　folding,　and　simulations　for　various　typical　RNA　motifs　indicate　that　BSFF2　should　be　one　of　valuable　tools　for　dynamic　conformation　research　and　structure　prediction　of　RNA,　and　a　future　contribution　to　RNA-targeted　drug　design　as　well　as　RNA　therapy　development.　©　2024　American　Chemical　Society.