Objective To analyze the feasibility of adaptive iterative low-dose dual-phase scanning in thyroid CT examination. Methods A prospective study was conducted on 80 cases of patients with thyroid nodules diagnosed by color Doppler ultrasound. According to the order of treatment, the first 40 patients undergoing conventional dual-phase scanning were included into the control group while the latter 40 patients undergoing adaptive iterative low-dose dual-phase scanning by randomly setting 3 groups of different tube voltages were included into the experimental group. The image noise and signal to noise ratio (SNR) were determined, and the image quality was evaluated objectively. Results There was no significant difference in the image quality of thyroid low-dose AIDR dual-phase scanning and conventional scanning, and there was no significant difference in SNR and noise ratio (P>0.05). The radiation dose of 80Kv ADIR lowdose scanning was the lowest. Conclusion The application of dual-phase multi-slice spiral CT adaptive iterative low-dose scanning in thyroid CT examination not only can obtain good image quality but also can reduce the radiation dose and improve the safety of scanning, and 80Kv low-voltage ADIR low-dose scanning was the optimal condition.