Objective To assess the effectiveness of T1 nerve root transection for treating spastic hand contracture in patients with cerebral palsy. Methods A clinical data of 12 patients with spastic hand contracture caused by cerebral palsy, who admitted between March 2024 and February 2025 and treated with T1 nerve root transection, was retrospectively analyzed. There were 7 males and 5 females, with a mean age of 35.6 years (range, 13-67 years). Before operation, muscle tone was grading 3-4 according to the Modified Ashworth Scale (MAS); muscle strength of the affected hand was grading 2-4 for flexor muscles and grading 0-4 for extensor muscles according to the Medical Research Council (MRC) scale; hand function was grading 0-4 according to the modified House Functional Classification (HFC); upper limb function scoring was 5.5 (0.5, 10.3) according to the Action Research Arm Test (ARAT) score. Results All incisions healed by first intention, and no complication occurred. All patients were followed up 6-18 months (mean, 12.6 months). At last follow-up, the spastic contracture of the affected hand obviously reduced, the muscle tone decreased, and hand function improved. The MAS grade, HFC grade, and ARAT score all showed significant improvement when compared with preoperative values (P<0.05). However, there was no significant improvement in flexor or extensor muscle strength of the affected limb, and no significant difference in MRC grade between pre- and post-operation (P>0.05). Conclusion T1 nerve root transection is a safe and effective treatment for spastic hand contracture in patients with cerebral palsy. It can significantly reduce muscle tone, relieve flexion contracture, and improve hand function. However, it does not appear to improve muscle strength.