Objective: This study aimed to develop a surgical strategy–oriented classification system for patients with severe dynamic sagittal imbalance (DSI) through detailed radiological assessment. Methods: A total of 193 patients who underwent reconstructive surgery for severe DSI from 2016 to 2023 were retrospectively reviewed. Classification was based on three radiographic criteria: (1) apex location (Type  I: T12–L2; Type II: L3–L5), (2) apical segment angle (Type I: 45°; Type II: 20°, classified as A or B), and (3) apical segment rigidity (segmental motion ≥5°: −;

<5°: +). According to surgical strategy, patients were divided into group A (ACR with PSF) and group B (ACR with PSF plus PSO). Radiographic parameters, clinical outcomes, and complications were compared. Results: All patients were classified into eight subtypes (IA–, IA+, IB–, IB+, IIA–, IIA+, IIB–, IIB+). Patients with mild apical segment kyphotic deformity (Types IA, IIA) achieved satisfactory correction with ACR and PSF. In contrast, those with severe and rigid apical segment kyphotic deformity (Types IB+, IIB+) required additional PSO. Both groups showed significant postoperative improvement in radiographic parameters and clinical outcomes, but the group B had a higher rate of perioperative complications (p< 0.05). Conclusions: This classification effectively stratifies severe DSI based on morphologic and structural features and provides practical guidance for selecting appropriate surgical strategies. Additional PSO is recommended for Type IB⁺ and Type IIB⁺ deformities.