Objective To introduce a new approach of neurotization to treatment of the shoulder syndrome after the radical neck dissection by using transpositional anastomosis of C7 posterior root and the spinal accessory nerve to reconstruct the function of trapezius muscle. Methods From March 1999 to February 2001, 10 patients underwent the neurotization during the radical neck dissection. In the operation, the apo-cranial part of spinal accessory nerve was preserved from the trapezius muscle (gt;3.0 cm in length) and anastomosed to C7 posterior root. Objective physical examinations and electromyography were conducted before and after operation.One, 6 and 12 months after operation the trapezius muscle function after the transpositional anastomosis was evaluated. Results One, 6 and 12 months after operation, the recovery rates of each part were as follows: 9.8%, 68.9% and 73.5% in upper part; 4.7%, 73.6% and 69.4% in middle part; and 6.2%, 70.5% and 70.3% in lower part. The range of abduction motion of upper arm in 7 cases (70%) exceeded 90°. The mean maximal abduction angle was more than 95°. Evaluation of the shoulder function showed that myoatrophy was mild and the disability of abduction was classified as grade Ⅱ in 7 cases and grade Ⅲ in 3 cases. Conclusion Transpositional anastomosis of the C7 posterior root to thespinal accessory nerve after radical neck dissection can well reconstruct the function of trapezius muscle. This approach provides a wide indication in comparison with the functional neck dissection without impairment of arm function afterthe cutting of C7.