The invention provides a rice disease-resistant regulatory gene, named as OsASR2. The open reading frame of the gene is 549bp long and encodes ASR protein which is composed of 182 amino acids. The gene encoding protein contains an ABA/WDS structure field. By constructing the OsASR2 gene expression inhibited RNAi rice, the invention discloses the regulatory action of the gene on the resistance to rice bacterial stripe for the first time. An OsASR2-RNAi plant exhibits strong resistance to rice bacterial stripe, thereby revealing that the OsASR2 gene has a strong negative regulatory function on the resistance to rice bacterial stripe. The invention also provides application of the OsASR2 gene to acquisition of a rice new material with strong resistance to rice bacterial stripe through developing the RNAi rice. The OsASR2 gene provided by the invention is a new gene resource suitable for developing and breeding rice new materials and new species with high resistance to rice bacterial stripe.