GROWTH REGULATING FACTOR 7 (OsGRF7) enhances rice salt tolerance by regulating arbutin metabolism. OsGRF7 promotes salt tolerance by increasing arbutin content, which rescues the salt-sensitive phenotype of OsGRF7 knockdown and knockout plants. OsGRF7 directly activates the expression of arbutin biosynthesis genes, OsUGT1 and OsUGT5, and their knockout reduces salt tolerance and grain size. OsGRF7 degradation via interaction with OsFBO13 reduces salt tolerance and grain size. These findings highlight OsGRF7's role in modulating rice arbutin metabolism, salt stress response, and grain size, with potential applications in rice breeding. Arbutin improves salt tolerance by reducing reactive oxygen species (ROS) and enhancing ROS-scavenging enzyme activities. OsGRF7 directly regulates arbutin biosynthesis by modulating OsUGT1 and OsUGT5 expression. OsFBO13 interacts with and degrades OsGRF7, negatively regulating salt stress response and grain size. OsGRF7's ubiquitination at lysine residue K365 is crucial for its degradation. OsGRF7's role in salt tolerance and grain size is mediated through OsUGT1 and OsUGT5. The OsGRF7-OsUGT1/OsUGT5-arbutin regulatory module is vital for rice salt stress response and grain development. This study provides insights into the molecular mechanisms underlying rice salt tolerance and grain size regulation, with implications for improving rice breeding and stress resistance.GROWTH REGULATING FACTOR 7 (OsGRF7) enhances rice salt tolerance by regulating arbutin metabolism. OsGRF7 promotes salt tolerance by increasing arbutin content, which rescues the salt-sensitive phenotype of OsGRF7 knockdown and knockout plants. OsGRF7 directly activates the expression of arbutin biosynthesis genes, OsUGT1 and OsUGT5, and their knockout reduces salt tolerance and grain size. OsGRF7 degradation via interaction with OsFBO13 reduces salt tolerance and grain size. These findings highlight OsGRF7's role in modulating rice arbutin metabolism, salt stress response, and grain size, with potential applications in rice breeding. Arbutin improves salt tolerance by reducing reactive oxygen species (ROS) and enhancing ROS-scavenging enzyme activities. OsGRF7 directly regulates arbutin biosynthesis by modulating OsUGT1 and OsUGT5 expression. OsFBO13 interacts with and degrades OsGRF7, negatively regulating salt stress response and grain size. OsGRF7's ubiquitination at lysine residue K365 is crucial for its degradation. OsGRF7's role in salt tolerance and grain size is mediated through OsUGT1 and OsUGT5. The OsGRF7-OsUGT1/OsUGT5-arbutin regulatory module is vital for rice salt stress response and grain development. This study provides insights into the molecular mechanisms underlying rice salt tolerance and grain size regulation, with implications for improving rice breeding and stress resistance.