The present invention discloses a method for improving the sensitivity of a plant on a gibberellin inhibitor, and applications thereof. The method comprises: introducing the encoding gene of a protein into a recipient plant to obtain a transgenic plant, wherein the sensitivity of the transgenic plant on the gibberellin inhibitor is increased compared to the recipient plant, and the protein is the following protein a) or b) or c) that: a) the amino acid sequence of the protein comprises amino acids at sites 1-821 in the sequence 1, (b) the protein comprises an amino acid sequence represented by the sequence 1, and (c) the protein is a fused protein formed by linking a tag to the N terminal or/and C terminal of protein a) or protein b). According to the present invention, the experiment results prove that the sensitivity of the plant on the gibberellin inhibitor can be improved with the method, and the height of the plant can be regulated by using the plant height related protein HRP.