The invention relates to the technical field of a lymphedema external preparation, in particular to an external composition and gelata for treating lymphedema, and a preparation method of the gelata.The external composition provided by the invention comprises a radix et rhizoma rhei extract, a fungus umbellatus extract, an argy wormwood leaf extract, a saffron extract, panax notoginseng saponins,bisabolol, glycyrrhetinic acid and mint camphor. The components of the composition are in synergistic reaction, and the composition has excellent efficacy of inducing diuresis for removing edema, promoting blood circulation to stop pain, resisting inflammation and bacteria, preventing skin tissue infection, and promoting skin external injury healing. The gelata provided by the invention comprisesthe external composition, a multi-functional transdermal absorption accelerant and substrate auxiliary materials, wherein the multi-functional transdermal absorption accelerant can effectively promote transdermal absorption and effective utilization of active components in the external composition, can achieve the effect of assisting in treatment of lymphedema, and can realize mutual complementing, and the treatment effect on the lymphedema is increased. The using method of the gelata is simple, and the gelata is low in cost, and portable and can be used at any time.