The　nanocarrier-based　delivery　system　has　emerged　as　a　promising　candidate　for　cancer　therapy;　nevertheless,　their　quality　problems,　variation　between　batches,　and　carrier-related　toxicity　issues　have　restricted　their　clinical　utilization.　Compared　with　traditional　carrier-based　nanoparticles,　carrier-free　nanodrug　delivery　systems　preferred　to　overcome　all　these　drawbacks　and　will　have　a　wide　range　of　applications　in　biomedicine　and　nanotechnology.　Herein,　we　developed　a　novel　carrier-free　nanodrug　Asp-UA　consisted　of　the　classical　drug　aspirin　and　the　natural　plant　drug　UA　via　a　green　and　simple　approach.　The　Asp-UA　NPs　were　investigated　for　shape,　particle　size,　zeta　potential,　stability,　and　UV-vis　spectroscopy　absorption.　Cellular　uptake　study　showed　that　Asp-UA　NPs　could　be　easily　internalized　by　HepG2　cells;　cellular　study　demonstrated　that　Asp-UA　NPs　held　better　inhibitory　efficiency　on　tumor　metastasis　with　low　toxicity　in　vitro　and　in　vivo.　Moreover,　Asp-UA　NPs　could　obviously　suppress　the　progress　of　cancer　metastasis　by　H22　cells　in　vivo.　Overall,　Asp-UA　NPs　possess　a　variety　of　advantages　and　hold　promise　to　become　an　alternative　to　the　treatment　of　cancer　metastasis.　©　Copyright　2018　American　Chemical　Society.