Ursolic acid is likely to become a new type of low toxicity and efficient anti-cancer drugs, because of its anti-carcinogenic, anti-tumor promoters, induce differentiation of F9 teratocarcinoma cells and anti-angiogenic effect.However, ursolic acid is insoluble ingredients and its bioavailability is very low.These shortcomings have limited its wide application.Liposome-encapsulated cancer therapeutics have shown to exhibit improved efficacies over non-encapsulated conventional drugs and folate receptor targeted liposomes can potentially enhance tumor cell uptake and antitumor efficacy of encapsulated drugs.Therefore, there are very few studies to evaluate the preparation of folate-targeted liposomal ursolic acid (FTL-UA) and its efficacy of anticancer.Folate-targeted Ursolic acid Stealthy Nano-liposomes can solve its solubility problem and improve bioavailability.In this study, we investigated the antitumor potential of FTL-UA in vitro and in vivo as a novel agent for the treatment of KB tumors.In vitro analysis of antitumor activity against human KB cell lines, showed a significant concentration and time-dependent manner and the inhibition of the proliferation of KB cells following exposure to FTL-UA as compared to non-targeted PEGylated liposomal ursolic acid (PL-UA) (at 72 h, IC50: 30μM·L-1 vs.210μM·L-1).The cell cycle analysis and apoptosis assay results suggested that FTL-UA was more effective than PL-UA on activation of apoptosis of KB cells.In vivo the antitumor activity of FTL-UA was investigated in Balb/c nu/nu mice bearing KB xenografts.Mice were treated tail intravenous injection of free UA, PL-UA, or FTL-UA (4.5mg/Kg, respectively) for five times every other day.We observed a great higher inhibition of tumor growth in mice treated with FTL-UA versus PL-UA and free UA, translated in obvious anti-tumor advantage of FTL-UA treated animals versus other groups.We conclude that FTL-UA is an effective agent against KB and exhibits higher antitumor activity as compared to free UA and PL-UA with no appreciable increase in toxicity.These results provide the feasibility of preclinical research for FTL-UA and clinical development for the treatment of KB patients.