The invention relates to a rice beta-amylase BA2 and a coding gene and application thereof. The amino acid sequence of the rice beta-amylase BA2 is shown as SEQ ID No.6 or the amino acid sequence withthe same function in which one or more amino acids are substituted, deleted or added, and the nucleotide sequence coded by the gene of the rice beta-amylase BA2 is shown as SEQ ID No.1 or has 80% homology with the sequence. The rice beta-amylase BA2 is driven by a pollen specific promoter to degrade starch in advance when being expressed in the pollen development period, and the rice beta-amylaseBA2 cannot provide energy for pollen germination, so that the pollen germination is restrained, and pollen abortion occurs. The rice beta-amylase BA2 can effectively prevent the transgenic pollen from escaping, can also be used for maintaining the homozygous recessive state of a male sterile plant, saves a manual emasculation step in the hybrid seed production process, and has wide application prospects in the aspects of crop germplasm resource improvement and genetic breeding.