Objective To study the imaging features and diagnostic value of ultrasonography and CT in the diagnosis of thyroid cancer. Methods 125 cases of thyroid cancer patients in the hospital during August 2011 to August 2014 were selected as the research object and all received CT and ultrasonography diagnosis. The detection rates of pathological types of thyroid cancer were compared between the two kinds of detection methods. The diagnosis of microcarcinoma lesions was observed. Finally, the diagnostic value of combined detection was analyzed. Results The positive rate of CT diagnosis was 75.2% which was significantly higher than 60.0% of ultrasonography (χ2 =6.593, P ＜0.05); The coincidence rate of CT in diagnosis of papillary microcarcinoma was 25.0% which was relatively higher than 18.8% of ultrasonography but there is no statistical significance (P＞0.05); The positive rate of CT and ultrasonography combined detection was 84.0% which was significantly higher than that of CT or ultrasonography single detection (P＜0.05). Conclusion The detection rate of CT in thyroid cancer is better than that of ultrasonography diagnosis, combined detection can improve the detection rate of thyroid cancer, which is of relatively higher clinical application value.