Gummosis in peach is an invasive disease that causes widespread and serious damage. Mechanical damage and ethylene (ETH) can induce gummosis in peach shoots in the field. In this study, we found that silicon can induce the synthesis of polyamines (PAs) and reduce the synthesis of ETH, thereby inhibiting gummosis in peach. The results showed that silicon (Si) can decrease the rate of gummosis, reduce the expression level of PpACS1 and reduce the enzyme activity of polygalacturonase (PG). Simultaneously, the expression level of PpSAMDC and the PAs content were increased and the ETH synthesis rate was decreased. Si inhibits the synthesis of ETH by promoting PAs synthesis. It was further discovered that Si can regulate the gene expression of PpERF21 and PpERF27. Yeast one-hybrid and dual-luciferase reporter assays showed that PpERF21 and PpERF27, through direct interaction with the promoter of PpPG1, inhibited the transcriptional activation of PpPG1. Overexpression of PpERF21 and PpERF27 effectively reduced fruit colloid production when bacterial cells harbouring the expression vector were used to instantaneously infect peach fruit. These results show that Si can inhibit the synthesis of ETH by promoting PAs synthesis, mediating PpERF21 and PpERF27 expression to inhibit the expression of PpPG1, thereby inhibiting gummosis in peach.