By using medical image process system for DNA contents,26 cases of thyroid tumors that comprised adenoma 5,panillary adenocarcinoma 14,follicular carcinoma 5,undifferentiated carcinoma 2 and normal thyroid tissue 3 were detected.The DNA contents in the number of polyploidy were:carcinoma the highest in amount,adenoma the medium and normal thyroid tissue the least,hence we propose that the determination of DNA ploidy in thyroid tumors may be used as an adjuvant to evaluate the proliferative activity of thyroid tumor.