Background and Aims Secondary hyperparathyroidism (SHPT) is one of the most challenging complications of chronic kidney disease (CKD), characterized by a series of calcium and phosphorus metabolism disorders, osteomalacia, and malabsorption, which severely affects the quality of life of patients. Currently, clinical treatment is unsatisfactory, and no ideal target molecules have been discovered. This study was conducted to identify candidate target molecules for SHPT, so as to provide new targets for its treatment.Methods The specimens of 5 fresh normal parathyroid tissues and 15 SHPT patient parathyroid tissues were collected from the Department of Pathology of Xiangya Hospital between 2017 and 2020. Among them, 2 normal parathyroid tissues and 5 SHPT patient parathyroid tissues were used for RNA transcriptome sequencing to obtain the differentially expressed genes, and the core genes were identified through functional enrichment analysis, PPI network construction and topology algorithms. The expressions of the core genes in the remaining normal parathyroid tissues and SHPT patient parathyroid tissues were validated using qRT-PCR and Western blot, respectively. Immunohistochemical staining was performed to detect the expressions of the core genes in the paraffin sections of 36 SHPT patient parathyroid tissues, and 16 normal parathyroid tissues that were inadvertently resected during thyroid surgery.Results A total of 1 323 differentially expressed genes were identified by RNA sequencing, and 10 key genes were screened through construction of PPI network and topological algorithm. Among them, dipeptidyl peptidase 4 (DPP4) was further validated due to its close association with diabetes. Results of qRT-PCR showed that the mRNA expression level of DPP4 in the parathyroid tissue of SHPT patients was significantly higher than that in normal parathyroid tissue (P=0.005 1); results of Western blot showed that the protein expression level of DPP4 in the parathyroid tissue of SHPT patients was significantly higher than that in normal parathyroid tissue (P=0.006 0); results of immunohistochemical staining showed that the positive rate of DPP4 in the parathyroid tissue of SHPT patients was significantly higher than that in normal parathyroid tissue (P=0.006 9).Conclusion The expression level of DPP4 is significantly upregulated in the parathyroid tissue of patients with SHPT, indicating that DPP4 may be involved in the occurrence and development of SHPT, and may be a potential therapeutic target for drug treatment of SHPT.