An oral microemulsion of elemene is disclosed. The microemulsion is made of elemene, surfactant, cosurfactant and water or buffer solutions with pH 5˜8. Said surfactant is selected form tweens, polyoxyethylene castor oils, polyethylene glycol stearates and mixture thereof. Said cosurfactant is selected from ethanol, 1,3-propanediol, glycerol and mixture thereof. The concentration of elemene in the microemulsion is 1˜5 g/100 ml. The ratio of elemene, surfactant and cosurfactant is 1˜5(weight):1˜40(weight):1˜40(volume), wherein the unit of weight/volume is g/ml.
