Ursolic　acid　(UA),　a　natural　pentacyclic　triterpenoid,　possesses　widespread　biological　and　pharmacological　activities.　However,　drawbacks　such　as　low　bioavailability,　poor　targeting　and　rapid　metabolism　greatly　hinder　its　further　clinical　application.　Recently,　with　the　development　of　nanotechnology,　various　UA　nanosystems　have　emerged　as　promising　strategies　for　effective　cancer　therapy.　This　article　reviews　various　types　of　UA-based　nano-delivery　systems,　primarily　with　emphasis　placed　on　novel　UA-based　carrier-free　nano-drugs,　which　are　considered　to　be　innovative　methods　for　cancer　therapy.　Moreover,　this　review　presents　carrier-free　nano-drugs　that　co-assembled　of　UA　and　photosensitizers　that　displayed　synergistic　antitumor　performance.　Finally,　the　article　also　describes　the　development　and　challenges　of　UA　nanosystems　for　future　research　in　this　field.　Overall,　the　information　presented　in　this　review　will　provide　new　insight　into　the　rational　utilization　of　nano-drugs　in　cancer　therapy.　(c)　2020　Shenyang　Pharmaceutical　University.　Published　by　Elsevier　B.V.　This　is　an　open　access　article　under　the　CC　BY-NC-ND　license.　(http://creativecommons.org/licenses/by-nc-nd/4.0/)