Developmental epileptic encephalopathies (DEEs) are a group of disorders characterized by early-onset seizures, abnormal electroencephalogram (EEG) patterns, and developmental delay or regression. They are characterized by complex etiology and are often refractory to treatment, severely impacting affected children, particularly infants and toddlers, and pose a challenge in pediatric neurology. In recent years, with the rise of precision medicine, an increasing number of pathogenic genes associated with DEEs have been discovered. However, the specific pathogenic mechanisms and signaling pathways of these genes in the body still require further investigation. This article primarily discusses the genetic patterns of DEEs and the selection of genetic testing, emphasizing the timing of genetic testing assisted by the epilepsy phenotype, especially in DEEs associated with single-gene mutations and new therapeutic drugs, to aid in clinical decision-making for DEEs. It also introduces the use of neurobiological models for DEE research to effectively advance epilepsy research, thereby enabling targeted gene therapy.