Micro(nano)plastics　(MNPs)　are　emerging　pollutants　that　can　adsorb　pollutants　in　the　environment　and　biological　molecules　and　ultimately　affect　human　health.　However,　the　aspects　of　adsorption　of　intracellular　proteins　onto　MNPs　and　its　biological　effects　in　cells　have　not　been　investigated　to　date.　The　present　study　revealed　that　100　nm　polystyrene　nanoplastics　(NPs)　could　be　internalized　by　THP-1　cells　and　specifically　adsorbed　intracellular　proteins.　In　total,　773　proteins　adsorbed　onto　NPs　with　high　reliability　were　identified　using　the　proteomics　approach　and　analyzed　via　bioinformatics　to　predict　the　route　and　distribution　of　NPs　following　cellular　internalization.　The　representative　proteins　identified　via　the　Kyoto　Encyclopedia　of　Genes　and　Genomes　pathway　analysis　were　further　investigated　to　characterize　protein　adsorption　onto　NPs　and　its　biological　effects.　The　analysis　revealed　that　NPs　affect　glycolysis　through　pyruvate　kinase　M　(PKM)　adsorption,　trigger　the　unfolded　protein　response　through　the　adsorption　of　ribophorin　1　(RPN1)　and　heat　shock　70　protein　8　(HSPA8),　and　are　chiefly　internalized　into　cells　through　clathrin-mediated　endocytosis　with　concomitant　clathrin　heavy　chain　(CLTC)　adsorption.　Therefore,　this　work　provides　new　insights　and　research　strategies　for　the　study　of　the　biological　effects　caused　by　NPs.