Abstract: The GH3 gene family, known as an early responsive gene to auxin, is crucial in plant growth, development, and stress response. This study utilized bioinformatics analysis on P. notoginseng genome data to identify and analyze the members of the GH3 gene family. RNA-seq and qRT-PCR were employed to study the expression of PnGH3 family members under A. panax stress. The results revealed that 15 GH3 gene family members in the P. notoginseng genome, unevenly distributed across 7 chromosomes. Phylogenetic analysis classified the PnGH3 gene family into three subgroups, with predominant distribution in subgroups Ⅰ and Ⅲ. Gene structure and motif analysis indicated that the same subgroup had similar exon/intron number and conserved motif distribution. Promoter analysis highlighted the presence of cis-acting elements related to light response, plant hormone response, stress response, and plant growth and development. Collinearity analysis suggested that the expansion of P. notoginseng GH3 family members was primarily due to segmental duplication events, showing structural and functional similarities with GH3 gene family members of A. thaliana and M. esculenta. RNA-seq and qRT-PCR analysis demonstrated that PnGH3.1 and PnGH3.9 were significantly up-regulation under A. panax stress, which indicates their key role in P. notoginseng response to A. panax infection.