Objective To explore the etiology, early diagnosis and identification, clinical characteristics, treatment and prognosis of hyperthyroidism in premature infants, and provide evidence for clinical diagnosis and treatment of hyperthyroidism in premature infants, and review the related case reports of hyperthyroidism in premature infants.Methods The clinical data of a very premature infant with hyperthyroidism were reported, and the related literature was reviewed. Results A very premature infant suddenly developed hyperthyroidism symptoms on the 8th day after birth, and was discharged after improving various examinations, early active emergency treatment and treatment. Hyperthyroidism in very premature infants was rare. This paper reviewed the literature and summarized 18 cases of premature infants, among which the gestational age was the smallest 29 weeks and the largest 36+5 weeks. There were 12 premature infants (66.7%), 4 premature infants (22.2%) and 2 very premature infants (11.1%). The earliest onset age was 1 day after birth, and the latest was 30 days after birth. Among 18 premature infants, the mother had thyroid diseases before or during pregnancy. The main clinical symptoms were tachycardia, shortness of breath, irritability, emaciation/slow/no weight gain. 11 cases were followed up for 2 months to 4.5 years, 2 cases were followed up for 7 years with poor learning ability, and 1 case was followed up for 8 months with poor development and advanced bone age. Conclusion Hyperthyroidism in premature infants can lead to multiple organ failure and life-threatening. Clinical attention should be paid to it, and early identification, diagnosis and treatment should be done well, and the prognosis is generally good