cases of thyroid benign and malignant nodules were selected as observation objects, all of them were examined by emission computed tomography(ECT), B ultrasound and computed tomography(CT), specimens were sent to pathological examination after thyroid surgery, and the results of pathological examination were taken as gold standard, to analyze the diagnostic value of ECT, B ultrasound and CT alone or in combination. There were 108 cases diagnosed as thyroid cancer in 121 patients. The sensitivity and accuracy of ECT combined with B ultrasound and CT in diagnosis of thyroid cancer were significantly higher than those of single diagnosis(P＜0.05), and there was no significant difference between the combined diagnosis specificity and the single diagnosis(P＞0.05), and there was no significant difference in specificity, sensitivity and accuracy between b ultrasound, CT and ECT(P＞0.05). Therefore, ECT combined with B ultrasound and CT can effectively improve the sensitivity and accuracy of thyroid cancer diagnosis, which can be incorporated into the diagnosis and treatment program to assist clinical diagnosis.