Abstract: 【Objective】 This study aimed to clone the sucrose non-fermenting-1-related protein kinase 2.4 gene of Catharanthus roseus （CrSnRK2.4）， analyze its expression pattern， and to investigate the regulatory effects of CrSnRK2.4 gene in biosynthesis of terpenoid indole alkaloids （TIAs） in Catharanthus roseus and stress response mechanisms， thus providing a theoretical basis for regulating biosynthesis and increasing yield of TIAs.【Method】 The CrSnRK2.4 gene was cloned， and bioinformatics methods were used to analyze its physiochemical properties and phylogeney of CrSnRK2.4 protein. The tissue-specific expression of CrSnRK2.4 gene and its response to different biotic and abiotic stresses were detected by real-time fluorescence quantitative PCR. The virus-induced gene silencing （VIGS） technology was used to transiently silence the CrSnRK2.4 gene to analyze effects of CrSnRK2.4 gene silencing on relative expression of three key enzyme genes in biosynthetic pathway of TIAs （CrSTR， CrG10H， and CrTDC） and contents of two TIAs （vindoline and catharanthine） in Catharanthus roseus.【Result】 The CrSnRK2.4 gene was identified and cloned from the genome of Catharanthus roseus， with a coding sequence （CDS） of 1071 bp， encoding 356 amino acid residues. The CrSnRK2.4 protein contained 26 potential phosphorylation sites， and the secondary structure was composed of α-helixes （39.045%）， random coils （43.820%）， and extended strands （17.135%）， which were located in nucleus. Multiple sequence alignment analysis showed that SnRK2.4 proteins of different species were highly conserved. Phylogenetic analysis showed that CrSnRK2.4 protein was most closely related to StSnRK2.4 protein of Solanum tuberosum. Real-time fluorescence quantitative PCR showed that the relative expression of CrSnRK2.4 gene in different tissues of Catharanthus roseus followed the order： the first pair of leaves>the second pair of leaves>the third pair of leaves>stems>roots>flowers. The relative expression of CrSnRK2.4 gene was significantly up-regulated under biotic stresses such as pathogenic microorganisms and insect pests， and abiotic stresses such as drought， salt， heat， and low temperature. After transient silence of CrSnRK2.4 gene， the relative expressions of key enzyme genes of TIAs biosynthesis pathway of CrSTR， CrG10H， and CrTDC in Catharanthus roseus， significantly decreased， accompanied by a significant reduction in the contents of vindoline and catharanthine.【Conclusion】 The CrSnRK2.4 protein has typical ATP-binding sites and protein kinase activation sites of SnRK2 family members. The CrSnRK2.4 gene is involved in the response of Catharanthus roseus to stresses such as drought， extreme temperatures， and pathogenic microorganisms. The CrSnRK2.4 gene is also involved in regulating the expression of key enzyme genes of TIAs biosynthesis pathway of Catharanthus roseus， thereby influencing the yield of TIAs， which may play an important role in the defense system of Catharanthus roseus.