Abstract: The early response of plant auxin gene family Aux/IAA (auxin/indole-3-acetic acid) and its interaction with auxin response factor (ARF) are important pattern to regulate plant growth and development. This work identified 28 StoIAA and 24 StoARF members based on the whole genome data of the medicinal plant Senna tora L., which were classified into 10 and 8 subfamilies, respectively. Phylogenetic tree and collinearity analysis showed that S. tora has close evolutionary relationship with the IAA and ARF homologous genes of Glycine max, Medicago truncatula, and the segment duplication events dominate the expansion of StoIAA and StoARF. Gene structure analysis showed that the vast majority of StoIAA and StoARF contain characteristic conserved domain. Transcriptome data showed that StoIAAs and StoARFs were expressed in leaves, roots and seeds, some members had tissue specific expression. The StoIAA and StoARF promoter region most contain functional elements related to stress response, growth and development, hormone induction and secondary metabolism. In addition, gene expression analysis showed that many StoIAAs and StoARFs can quickly respond to drought and salt stress and exhibited same expression patterns under both stress condition. The yeast two-hybrid experiment confirmed that StoARF8 and StoARF10 exhibit varying degrees of interaction with multiple StoIAA proteins, respectively. The above results provide a basis for further biological functional analysis of the Aux/IAA and ARF gene family of S. tora.