Objective To investigate the thyroid cancer using small MRI, CT, B ultrasonic three detection methods of comparative analysis of the effect of its diagnosis. Methods A retrospective analysis of our hospital in September 2013 to July 2015 for treatment of the information is complete 180 cases of thyroid cancer in patients with small, all patients were over three detection through MRI, CT, B patterns on their diagnosis, diagnosis and disease Neo diagnostic results were compared, respectively, the positive rate of thyroid microcarcinoma statistics three detection modes. Results The results of this study, the tiny thyroid cancer MRI positive rate of 32.22% (58/180), CT positive rate of 33.89% (61/180), B super-positive rate of 74.44% (134/180), MRI between positive rate compared with CT, the difference was not statistically significant, was not statistically significant (χ2 =0.11, P>0.05), the difference was significant between, MRI, CT and B-positive rate of detection, there was statistically significant (χ2 =64.46, P<0.01, χ2 =59.63, P<0.01). Conclusion Thyroid microcarcinoma of MRI, CT, B super three detection methods, the positive rate of B-test of the highest, has a strong guiding significance for clinical diagnosis, it is worth promotion clinically.