The invention relates to the field of medicinal chemistry, and discloses applications of any compound from benzimidazole derivatives Y-0 to Y-12 in prevention and treatment of agricultural plant diseases. It is found through bioactivity test that compounds have certain inhibition activity on six plant fungi including Phyllosticta zeae, botrytis cinerea, sclerotinia sclerotiorum, magnaporthe grisea, rhizoctonia solani and fusarium oxysporum, the inhibition rate of part of the compounds on the six pathogenic fungi under 100 ppm reaches 70% or above, and particularly, the growth of Phyllosticta zeae is almost completely inhibited. The compounds are simple to prepare and cheap and easily available in raw materials, and are expected to be developed into novel bactericides.