The invention relates to the technical field of pesticides, in particular to a pesticide composition which contains isoproturon, flucarbazone and diflufenican and is used for preventing and killing off gramineous weeds and broadleaf weeds in wheat fields. The pesticide composition is prepared from active ingredients and auxiliary ingredients, the active ingredients comprise isoproturon, flucarbazone and diflufenican, the mass ratio of isoproturon to flucarbazone to diflufenican is 1:(1.2-1.8):(1-2), the mass sum of isoproturon, flucarbazone and diflufenican accounts for 5%-80% of the mass of the composition, and the auxiliaries ingredients comprise at least one of a dispersing agent, an emulsifying agent, a wetting agent, a binding agent, an anti-freezing agent and a thickening agent. According to the pesticide composition containing isoproturon, flucarbazone and diflufenican, a synergistic effect is exerted within a certain proportion range, the prevention and control effect of the composition is obviously improved compared with a single component, the pesticide dosage is reduced, the pesticide use frequency is decreased, the pesticide cost is reduced, the negative influence of pesticide on ecological environment is reduced, and keeping of ecological balance is facilitated.