The invention belongs to the technical field of colloidal gel, and relates to carrageenan gel, in particular to Iota type carrageenan and Kappa type carrageenan mixed gel and a preparation method thereof. The invention discloses the Iota type carrageenan and Kappa type carrageenan mixed gel and the preparation method thereof. The Iota type carrageenan and Kappa type carrageenan mixed gel specially consists of the following components in parts by mass: 3-6 parts of Iota type carrageenan, 2-4 parts of Kappa type carrageenan, 1-2 parts of alanine, and 1000 parts of water. The preparation method comprises the following steps: performing swelling at normal temperature, performing heating swelling, performing heating blending and cooling the gel. According to the Iota type carrageenan and Kappa type carrageenan mixed gel disclosed by the invention, a low concentration carrageenan mixture of 0.5%-1.0% can form gel, and the prepared gel is high in transparency, moderate in hardness, elastic, not liable to dehydration, high in gel strength and good in storing stability at normal temperature. The method is simple in steps, convenient to operate, time-saving and labor-saving.