Abstract: Cytochrome P450 (CYP450) is a kind of superfamily oxidase containing heme, which is distributed in various aerobic organisms. They are widely involved in the biosynthesis of terpenoids, alkaloids, flavonoids, fatty acids, etc. In this study, the full-length cDNA sequence of a P450 was cloned by reverse transcription-PCR (RT-PCR) and rapid amplification of cDNA ends (RACE) technology, with the specific primers that designed according to the sequence of a transcript annotated as P450 from the Aquilaria sinensis (Lour.) Gilg transcriptome database. The tissue expression and subcellular localization were also studied. The full-length cDNA of the cloned P450 gene is 1 920 bp, with 88 bp 5′-untranslated region (UTR), 344 bp 3′-UTR and a 21 bp polyA tail, and 1 488 bp open reading frame (ORF), encoding 495 amino acids. Sequence alignment revealed that the protein belonged to CYP71D family of cytochrome P450 family, and named AsCYP71D1. Tissue expression analysis indicated that AsCYP71D1 was mainly expressed in stem. Further subcellular localization of onion epidermis showed that AsCYP71D1 was expressed in cytoplasm, nucleus and cell membrane. This study will provide a foundation for further research on its function in agarwood sesquiterpene biosynthesis.