Composite　additives　can　achieve　efficient　synergistic　effects　and　improve　friction　performance　of　lubricants.　The　development　of　high-performance　composite　additive　lubricating　grease　holds　significant　engineering　value　in　addressing　the　issue　of　maintaining　precision　in　precision　machinery　under　heavy-load/confined　space　conditions.　In　this　work,　SiO2　and　ZIF-8　mixed　structures　(S/Z)　and　core-shell　structures　(SiO2-core/ZIF-8-shell,　S@Z)　were　prepared.　The　effect　of　SiO2　and　ZIF-8　composite　nanoparticle　(NP)　additives　on　the　friction　performance　of　lithium-based　grease　under　mixed　lubrication　was　explored　by　the　experiment　and　molecular　dynamics　(MD)　simulations.　The　results　showed　that　the　combination　of　SiO2　and　ZIF-8　exhibited　significant　synergistic　effects.　Furthermore,　S@Z　was　characterized　by　better　friction　performance　than　S/Z.　Compared　to　the　original　lubricating　grease,　the　addition　of　S@Z　at　1.5　wt%　could　reduce　the　friction　coefficient　μ　and　wear　content　up　to　33.74　%　and　74.93　%,　respectively.　The　MD　simulation　was　consistent　with　the　experimental　results.　The　hard-core　SiO2　of　S@Z　played　a　rolling　and　supporting　role.　The　flexible　crystal　structure　of　the　ZIF-8　shell　produced　significant　deformation　to　adapt　to　rough　surfaces.　This　structure　avoided　the　rupture　of　the　lubricating　film　and　direct　contact　between　the　two　friction　surfaces,　improved　the　bearing　capacity,　and　prevented　SiO2　from　being　exposed　and　scratching　the　friction　surface　©　2024