Abstract: The auxin receptor TIR1, which can directly bind to auxin through the formation of the SCFTIR1 complex , is the key protein in the Aux /IAA degradation pathway of the 26S proteasome. In this research, we designed a specific primer according to the results of a BLAST search of bioinformatics data; the super hybrid rice parental line 1S was used as the plant material. After RT-PCR and T-A cloning, a 2 219 bp cDNA sequence was obtained through sequencing. Its open reading frame (ORF) was 1 764 bp long and coded for a polypeptide of 587 amino acids. Bioinformatics analysis revealed that the polypeptide shares 77% similarity with AtTIR1. Both polypeptides contain an F-box motif and a leucine-rich repeat domain but no transmembrane helices or signal peptide. The cDNA sequence was designated as OsTIR1 and submitted to GenBank.