The invention relates to a pesticidal composition for controlling maize brown spot, which consists of a systemic bactericide 1-(4-chlorphenyl)-3-(1H-1,2,4-triazole-1-methyl)-4,4-dimethyl pentane-3-alcohol, a polyhydric coordination compound of a protective fungicide manganese ethylene-bis-dithiocarbamate and zinc ions, a wetting agent, other additives and the like, and has the advantages of significantly improving the inhibition activity to the germination of hypnosporangium of germs of the maize brown spot and the effect of controlling field diseases, reducing the using amount of the systemic bactericide, improving the safety to maize seedlings, reducing the use cost, and delaying the occurrence of the resistance to the systemic bactericide, therefore, the pesticidal composition is suitable for seed treatment and field spray treatment so as to control the diseases such as the maize brown spot, rust disease and the like, and has significant economic, ecological and social benefits.