The invention discloses a wheat seed coating agent, which comprises an active component bactericide, a plant growth regulator, an inactive component coating agent and an aid, and concretely comprises the following components in percentage by weight: 0.5 to 2.0 percent of tebuconazole, 21 to 22.5 percent of thiram1.5 to 2.2 percent of concentrated emulsion No.500, 2.4 to 3.0 percent of concentrated emulsion No.600, 0.5 to 1.7 percent of di-secondary sodium sulfocyanate, 0.05 to 0.15 percent of xanthan gum, 0.3 to 4.0 percent of dimethicone, 4.5 to 5.5 percent of ethylene glycol, 0.5 to 2.0 percent of warning color and the balance of water. The total content of tebuconazole and thiram is 23 percent. The seed coating agent has the characteristics of high suspension rate, high coating property, uniform coating, low stripping rate, low toxicity, convenient use and the like. The seed coating agent to seed ratio is high, so the seed coating agent is economic to use, and the cost of the seed coating agent is lower than those of products of the same kind. The germination rate of the wheat seeds can be improved by 10 percent, the incidence of rust disease and dust-brand in wheat fields is reduced by about 30 percent, and the yield of the wheat is increased by over 10 percent.