Objective To investig the value of neck lymph dissection in re-operation for differentiated thyroid carcinoma (DTC) and direct the choice of re-operative pattern.Method Re-operation was performed in 122 cases with DTC,of which neck lymph dissection was performed in 88 cases and the clinical data were retrospectively analyzed.Of 88 cases,partial thyroidectomy was performed in 38 cases in the first operation,one lobe plus isthmus excision 16 cases,thyroiddectorny was perfomed in 2 cases,neck lymph nodes biopsy in 32 cases.Results 11 patients suffered from thyroid micro carcinoma.The metastasis rate of neck lymph node were 65.91% (58/88) and residual carcinoma rate was 31.59%(12/38). Conclusions Neck lymph dissection had definite curable effect on re-operation for DTC.Neck lymph dissection should be performed when tumor had involved capsule,enlarged lymph node was palpated in the neck and thyroid micro carcinoma was confirmed.Re-operation was necessary for recurrent thyroid carcinoma.Attention must be paid to the fullresection of recurrent lesions and preserving laryngeal nerve and parathyroid in re-operation.