The invention discloses a mosquito trap agent and a preparation method thereof. The mosquito trap agent is prepared from the following components in parts by weight: 50-70 parts of ethanol, 25-40 parts of fish oil, 10-15 parts of saccharides, 5-10 parts of amino acids, 5-8 parts of salts, 3-8 parts of lactic acid, 0.5-3 parts of ammonia water, 0.05-0.15 part of acetic acid, 0.2-0.5 part of rose essential oil, and several parts of water, wherein the saccharides are selected from at least one of glucose, sucrose and brown sugar, the salts are selected from at least one of fatty acid sodium salt,fatty acid potassium salt, sodium chloride, magnesium chloride and calcium chloride, and a volatile solvent is at least one of methanol, n-hexane and styrene. The mosquito trap agent not only has theadvantages of being no-toxic and free from side effects to the environment, but also is convenient to use, simple in production process, easy in availability of raw materials and low in production cost; the mosquito trap agent is prepared from the ethanol, the fish oil, the saccharides, the amino acids, the salts, the lactic acid, the ammonia water, the acetic acid, the rose essential oil and thewater, and the raw materials used by the mosquito trap agent are low in cost and emit strong odor, so that the insect trap range is wide, and the effect is good.