The invention relates to a kitchen cleaner and a preparation method thereof. The cleaner comprises the following components in percentage by weight: 1 percent to 5 percent of caustic soda liquid, 1 percent to 5 percent of sodium citrate, 1 percent to 4 percent of Berol226 (ethoxy alcohol and alkyl glycoside surfactant), 1 percent to 4 percent of FMEE (fatty acid methyl ester ethoxylate), 3 to 8 percent of glycol ether, 1 to 3 percent of N-methyl-2-pyrrolidone, 0.05 to 0.1 percent of TB10 consisting of Kathon and 2-bromo-2-nitro-1,3-propanediol, and the balance of water. The kitchen cleaner adopts an imported mixture with cation and non-ionic surface activity, has superstrong degreasing capacity, shows higher degreasing capacity when being compounded with a chelate and has excellent tolerance on both hard water and soft water. The kitchen cleaner can be kept stable under both the acid and alkali conditions, has excellent emulsifying capacity and capacity of preventing oil dirt from being redeposited, and is suitable for various surfaces. The cleaner has excellent fluidity, can rapidly soften dirt with various weights, dissolve the oil dirt into liquid and enable the liquid to be automatically dropped into an oil cup in any seasons under the non-disassembled condition, has high drying speed, is easy to polish, does not damage the surface of an enclosure and blades, and is not only convenient, but also safe. Anticorrosive sterilizing factors effectively inhibit bacterial colony from being bred. No matter novel or old range hood can achieve an ideal cleaning effect.