Phytoalexin plays an important role in plant immunity. However, the mechanism of how phytoalexin is induced by beneficial microorganisms against broad-spectrum pathogens remains elusive. This study showed that B. cereus AR156 could trigger ISR against broad-spectrum disease. RNA-seq and camalexin content assays showed that AR156-triggered ISR can induce the accumulation of phytoalexin such as camalexin synthesis and secretion-related genes. Moreover, it was found that AR156-triggered ISR elevates camalexin accumulation by increasing the expression of camalexin synthesis genes upon pathogen infection. Further studies revealed that WRKY33 was required for the induction of camalexin accumulation by AR156 during the pathogen infection. Compared to the control inoculated with Phytophthora capsici and Botrytis cinerea only, the biomass of P. capsici and B. cinerea in AR156 pretreated wrky33 mutant plants were quite similar. AR156-induced ISR resistance to Pseudomonas syringae pv. tomato DC3000 ( Pst DC3000) was significantly attenuated in the wrky33 mutant. Furthermore, the study reveals that AR156 could up-regulate the expression level of PEN3 and PDR12, which act as camalexin transporter. In addition, we found that PEN3 and PDR12 served as positive regulators involved in AR156-triggered ISR against pathogens. Specifically, PEN3 and PDR12 participated in AR156-triggered ISR against fungi and oomycetes, while PEN3 was involved in AR156-triggered ISR against Pst DC3000. In summary, B. cereus AR156 triggered induced systemic resistance against B. cinerea, Pst DC3000 and P. capsici by priming of phytoalexin synthesis and secretion. Our study first proposed that the WRKY33 as a core factor is involved in regulating AR156-induced accumulation and secretion of phytoalexin, and we deeply elucidated the mechanism of AR156-induced phytotoxin accumulation resistance to broad-spectrum pathogens.