SUMOylation is an important posttranslational modification of eukaryotes that is widely present in metabolic regulation processes under various stresses. SIZ1 is a SUMO E3 ligase that plays a key role in substrate-specific recognition and directly promotes the binding of SUMO proteins to target proteins. Here, we reviewed the characteristics of SUMO as well as SUMOylation and the role of the SUMO E3 ligase SIZ1 in plant adaptation to abiotic stresses such as abnormal temperature, drought, salinization, phosphorus and nitrogen deficiency, heavy metal and metalloid toxicity, light exposure and reactive oxygen species. This review will enhance our understanding of these stressors and provide a useful reference for appropriate crop improvement, especially in suboptimal environments. Moreover, we provide a reference for future research on the role of SUMOylation in plant responses to abiotic stress.