Objective Though TSH is closely related to the incidence and prognosis of thyroid carcinoma, the underlying mechanisms have not been elucidated. This study was to investigate whether thyroid stimulating hormone in papillary thyroid carcinoma can regulate the expression of Cpt1c and to investigate the effect of Cpt1c on TSH promoting the proliferation of papillary thyroid carcinoma cells. Methods Firstly, the expression of Cpt1c was detected by qRT-PCR in 35 papillary thyroid carcinoma specimens and their adjacent normal tissues from papillary thyroid carcinoma patients. Secondly, the effects of TSH on the expression the Cpt1c from B-CPAP was detected at time and concentration gradient respectively. Finally, Cpt1c siRNA was constructed and transfected into B-CPAP. Western blot and qRT-PCR were used to identify the siRNA transfection efficiency of tumor cells. After identification, CCK-8 and FACS were used to detect cell proliferation and cell cycle with stimulation of TSH. Results Cpt1c is highly expressed in human papillary thyroid cancer compared with paired normal tissues. TSH could promote the expression of Cpt1cin a dose-dependent manner. Cpt1c could affect the proliferation of thyroid cancer cells by S phase stagnation and the expression of Cpt1c in papillary thyroid carcinoma is higher than that in adjacent tissues. At the same time, TSH could promote Cpt1c expression caused by cells into the G2 phase to increase proliferation. Conclusions TSH could promote the proliferation of papillary thyroid carcinoma cells by regulating the expression of Cpt1c. Cpt1c gene may be a new target for the treatment of papillary thyroid cancer in the future.