PURPOSE Thyroid cancer is the most frequent malignancies of the endocrine system, and it has became the fastest growing type of cancer worldwide. Much still remains unknown about the molecular mechanisms of thyroid cancer. Studies have found that some certain relationship between ARAP3 and human cancer. However, the role of ARAP3 in thyroid cancer has not been well explained. This study aimed to investigate the role of ARAP3 gene in papillary thyroid carcinoma. METHODS Whole exon sequence and whole genome sequence of primary papillary thyroid carcinoma (PTC) samples and matched adjacent normal thyroid tissue samples were performed and then bioinformatics analysis was carried out. PTC cell lines (TPC1, BCPAP, and KTC-1) with transfection of small interfering RNA were used to investigate the functions of ARAP3 gene, including cell proliferation assay, colony formation assay, migration assay, and invasion assay. RESULTS Using next-generation sequence and bioinformatics analysis, we found ARAP3 genes may play an important role in thyroid cancer. Downregulation of ARAP3 significantly suppressed PTC cell lines (TPC1, BCPAP, and KTC-1), cell proliferation, colony formation, migration, and invasion. CONCLUSION This study indicated that ARAP3 genes have important biological implications and may act as a potentially drugable target in PTC.