Introduction　SARS-CoV-2　pandemic　has　presented　a　significant　threat　to　global　health　and　the　economy,　necessitating　urgent　efforts　to　develop　effective　antiviral　drugs.　The　main　protease　(3CLpro)　of　SARS-CoV-2　is　a　critical　target　for　antiviral　therapy　due　to　its　essential　role　in　viral　replication.Methods　In　order　to　find　new　structural　types　of　3CLpro　inhibitors　to　facilitate　the　solution　to　the　problem　of　new　virus　resistance.　Six　potential　pharmacologically　bioactive　compounds　were　identified　by　utilizing　structure-based　virtual　screening　and　in　vitro　assays　from　the　Topscience　database　containing　10　million　compounds.Results　and　Discussion　Among　these,　compounds　34　and　36　exhibited　potent　inhibitory　activity　with　IC50　values　of　6.12　+/-　0.42　mu　M　and　4.47　+/-　0.39　mu　M,　respectively.　To　elucidate　their　binding　mechanisms　with　3CLpro,　all-atom　molecular　dynamics　(MD)　simulations　were　conducted.　Principal　component　analysis　(PCA),　free　energy　landscapes　(FEL)　and　dynamic　cross-correlation　maps　(DCCM)　revealed　that　the　binding　of　compounds　34　and　36　to　3CLpro　significantly　enhanced　the　structural　stability　of　3CLpro,　reducing　conformational　flexibility　and　internal　motions.　The　results　of　protein-ligand　interaction　showed　that　compounds　34　and　36　formed　strong　and　stable　interactions　to　key　residues　at　active　site　of　3CLpro　with　different　binding　modes　from　S-217622.　And　HOMO-LUMO　gap　and　molecular　electrostatic　potential　distribution　revealed　the　quantum　chemical　properties　of　compounds　34　and　36.　These　findings　suggested　that　compounds　34　and　36　can　be　as　novel　SARS-CoV-2　3CLpro　inhibitors　and　promising　lead-like　drug　candidates　for　developing　COVID-19　treatments.