Background: Lennox-Gastaut syndrome (LGS) is one of the most severe childhood-onset epileptic encephalopathies, primarily characterized by tonic seizures. In clinical practice, we have identified various subtypes of tonic seizures in LGS. This study aimed to analyze the clinical characteristics, electrographic features, treatment responses, and prognosis across different subtypes of LGS. Methods: This retrospective cohort study included 46 patients diagnosed with LGS at our center between January 2017 and January 2020. Patients were classified into four groups based on tonic seizure subtypes: Group A (tonic), Group B (spasm-tonic), Group C (myoclonic-tonic), and Group D (combination of spasmtonic and myoclonic-tonic). Comprehensive clinical data were collected and analyzed. Results: Of the 46 patients, 33 were male. The mean age of onset for Group B (12.38 +/- 7.85 months) was significantly less than those of the other three groups (P 1/4 0.02). No significant differences in etiology were found among the groups. Genetic analysis identified mutations in SCN8A, MCCC2, STXBP1, GABRB3, and CACNA1H. After a minimum follow-up of 24 months, the treatment outcomes were more favorable in Groups A and C, whereas psychomotor development was notably poorer in Groups B and D. Conclusions: The findings of this study suggest that LGS may present with distinct subtypes of tonic seizures, with spasm-tonic seizures presenting at an earlier age. Patients with LGS experiencing spasmtonic seizures, with or without myoclonic-tonic seizures, exhibited poorer treatment responses and psychomotor development than those with other subtypes.