Papillary thyroid carcinoma, as a malignant tumor with high incidence, is often accompanied by Hashimoto's thyroiditis. The pathogenesis of papillary thyroid carcinoma has not been fully clarified, and new molecular diagnostic methods are urgently needed to help the early and accurate diagnosis. In this study, the proteomic characteristics of papillary thyroid carcinoma in the context of Hashimoto's thyroiditis were analyzed by mass spectrometry, and the corresponding differential proteins and key pathways were screened to further study the pathogenesis and development mechanism.