The invention relates to insect forage and a preparation method thereof. The insect forage uses jelly powder, carrageenan, agar powder, fructose and water as basic raw materials, and combining the raw materials to nutrition inertia material by a certain proportioning, so that the forage has certain hardness, has good water retention performance, and can satisfy water-intake amount for insect. In addition, because the insect forage is not added with any antiseptic, the insect forage does not influence growth of insect. The preparation method includes steps: drily mixing the fructose, jelly powder, carrageenan and a small amount of agar powder, adding water to the mixture under stirring condition until percentage content of water is 60%-75%, continuously stirring until solution is uniform, placing and soaking for 3-5 hours, heating the solution to completely dissolve the mixture, adding a edible antifoaming agent, adding an amount of citric acid and sodium citrate after filtering, in addition adding proper amount of fruit essence and artificial food coloring, and obtaining the insect forage after filling and sterilizing.