Objective To compare the effectiveness between laminoplasty with preservation of the unilateral spinous process-ligament complex and traditional laminoplasty for thoracolumbar intraspinal tumors. Methods A retrospective analysis was conducted on 91 patients with thoracolumbar intraspinal tumors, who met the selection criteria and were admitted between November 2019 and November 2024. Among them, 52 patients underwent traditional laminoplasty (control group), and 39 underwent laminoplasty with preservation of the unilateral spinous process-ligament complex (treatment group). There was no significant difference in baseline data between groups (P>0.05), including gender, age, body mass index, tumor type, involved segments, disease duration, smoking history, preoperative visual analogue scale (VAS) score, American Spinal Injury Association (ASIA) classification, Oswestry disability index (ODI), and selective functional movement assessment (SFMA). The two groups were compared based on the following outcome indicators, including operation time, intraoperative blood loss, length of hospital stay, occurrence of postoperative complications (e.g., cerebrospinal fluid leakage), as well as neurological function recovery (ASIA grading, ODI), pain level (VAS score), and spinal mobility and pain symptoms (SFMA). Results There was no significant difference between groups (P>0.05) in terms of operation time, intraoperative blood loss, length of hospital stay, or the incidence of cerebrospinal fluid leakage. All patients were followed up, with follow-up periods of (19.26±4.45) months for the treatment group and (18.63±4.42) months for the control group, showing no significant difference (t=?0.662, P=0.510). The postoperative VAS scores, ASIA grades, and ODI showed significant improvement compared to preoperative values in both groups (P<0.05). At 3 and 12 months after operation, there was no significant difference between groups (P>0.05). In the SFMA multi-stage trunk flexion and extension assessment at 3 and 12 months, there was no significant difference in motor function between groups among pain-positive cases (P>0.05). However, among function cases, there was a significant difference in the incidence of pain (P<0.05). Follow-up imaging showed that laminar fusion achieved in both groups, with no internal fixation failure or significant spinal instability. Conclusion Compared to traditional laminoplasty, laminoplasty with preservation of the unilateral spinous process-ligament complex demonstrates comparable results in terms of surgical safety, short-term neurological recovery, and complication control. However, its advantage lies in better maintaining dynamic spinal stability and significantly alleviating pain at the surgical site during spinal hyperflexion and hyperextension.