Femtosecond　laser-induced　surface　structures　upon　multiple　pulses　irradiation　are　strongly　correlated　with　the　pulse　number,　which　in　turn　significantly　affects　successive　laser-material　interactions.　By　recording　the　dynamics　of　femtosecond　laser　ablation　of　silicon　using　time-resolved　shadowgraphy,　here　we　present　direct　visualization　of　the　excitation　of　air　plasma　induced　by　the　reflected　laser　during　the　second　pulse　irradiation.　The　interaction　of　the　air　plasma　and　silicon　plasma　is　found　to　enhance　the　shockwave　expansion　induced　by　silicon　ablation　in　the　longitudinal　direction,　showing　anisotropic　expansion　dynamics　in　different　directions.　We　further　demonstrate　the　vanishing　of　air　plasma　as　the　pulse　number　increases　because　of　the　generation　of　a　rough　surface　without　light　focusing　ability.　In　the　scenario,　the　interaction　of　air　plasma　and　silicon　plasma　disappears;　the　expansion　of　the　silicon　plasma　and　shockwave　restores　its　original　characteristic　that　is　dominated　by　the　laser-material　coupling.　The　results　show　that　the　excitation　of　air　plasma　and　the　laser-material　coupling　involved　in　laser-induced　plasma　and　shockwave　expansion　are　structure　mediated　and　dependent　on　the　pulse　number,　which　is　of　fundamental　importance　for　deep　insight　into　the　nature　of　laser-material　interactions　during　multiple　pulses　ablation.　Copyright　©　2018　Qingsong　Wang　et　al.