Abstract: A miRNA, derivative and use thereof are disclosed. The miRNA comprises a nucleic acid sequence as shown in SEQ ID NO. 1 or a nucleic acid sequence obtained by modifying, substituting, deleting or adding at least one base to the nucleic acid sequence as shown in SEQ ID NO. 1. According to the disclosure, the used miRNA is derived from Glycine max, is safe to human beings and has no effect on a rice plant; and the derivative of the miRNA obtained by modification also retains the effects and characteristics of the miRNA, can be used as a novel insecticide for safely and effectively preventing and controlling brown planthopper, can be directly used on a transgenic plant, and has a practical application value for brown planthopper prevention and control.