Objective To explore the diagnosis and relapse factors of thyroid cancer. Methods Two hundreds fifty-six cases of thyroid cancer approved by surgery and pathology from 1999 to 2006 were analyzed retrospectively. Results Two hundred and thirty-five cases were approved papillary thyroid carcinoma (91.8%)，11 cases were follicular thyroid carcinoma (4.3%)， 7 cases were medullary thyroid carcinoma (2.7%)， 3 cases were anaplastic thyroid cancer (1.2%). All patients underwent surgery. The operation procedures included thyroidectomy and lymph nodes dissection in central zone of affecting side and subtotal thyroidectomy of contralateral side. Total or subtotal thyroidectomy of both sides and the dissection in unilateral or bilateral Ⅵ region lymph nodes or functional cervical lymph nodes dessection plus contralateral side Ⅵ region lymph nodes dissection in multi-focal cancer and double leaf gland cancer. Functional cervical lymph nodes dessection if existing lymph nodes metastasis or thyroid cancer invading anterior cervical muscle. Two hundreds twentyeight cases were followed up with complete clinical information about (6.5±1.3) years (3-9 years). Six cases died during follow-up because of relapse or metastasis.Conclusions Imaging evaluation is the main method for diagnosis of thyroid cancer. Needle biopsy is reliable and accurate for diagnosis of thyroid tumor. Diameter of tumor is related with cervical lymph node metastasis. Patho-type and stage of tumor, local invasion extent, lymph node metastasis and operation procedure are related with the relapse closely.