Abstract: Objective　To explore the anatomical features of fetal thyroid artery and its application value by means of cast blood vessel specimen and three-dimensional reconstruction technique.　Methods The filler were perfused through the common carotid artery and subclavian artery, and the thyroid artery vessels of 17 fetuses at around 18~37 weeks were anatomically observed and measured. The CT scan data were imported into Mimics 21.0 software for three-dimensional reconstruction of thyroid artery.　Results　The variation of fetal thyroid artery originated from the first branch of external carotid artery (accounting for 79.4%) or originated from the common carotid artery (accounting for 14.7%) or from the bifurcation of the common carotid artery (accounting for 5.9%)，the fetal inferior thyroid artery may originate from the thyrocervical trunk (accounting for 76.5%) or originate from the subclavian artery (accounting for 23.5%). The fetal thyroid artery branches and distribution were constant. There was no significant difference in the initial position between the adult thyroid artery and the fetal thyroid artery. There were significant difference in the branches and distribution between them.　Conclusions　Understanding the origin of thyroid artery, its branch and distribution characteristics can provide a practical basis for intrauterine fetal development research or neonatal clinical surgery.

Key words: Thyroid artery , 　Cast specimen, 　Anatomy, 　 Fetus