The invention discloses a pure natural grain kitchen ware cleaning agent and a preparation method thereof and belongs to the technical fields of cleaning agents and preparation methods thereof. The pure natural grain kitchen ware cleaning agent comprises the following components in parts by weight: 5.68-8.24 parts of KOH, 49.32-56.76 parts of rice bran oil, 45-55 parts of rice bran cakes and 500 parts of deionized water. The method for preparing the pure natural grain kitchen ware cleaning agent comprises the following steps: (a) preparing dewatered rice bran; (b) pressing oil from the rice bran; (c) preparing a semi-finished product A; (d) preparing a semi-finished product B; and (e) manufacturing the finished product. The product is natural and free of oil dirt and does not contain any chemical residue. The natural deoiling components in natural wheat and rice are extracted, oil stains on kitchen ware can be fully cleaned with the cleaning agent, and no chemical residue is left.