Objective To observe the protective effect of carbon nanonegative imaging on parathyroid gland during thyroid cancer surgery.Methods The clinical data of 100 patients with radical thyroidectomy treated in the First Affiliated Hospital of Nanjing Medical University from June 2021 to June 2023 were retrospectively selected.They were divided into observation group(n=50)and control group(n=50)according to different treatment methods.Both groups were treated with radical thyroidectomy,the observation group was treated with nano carbon negative imaging to protect parathyroid,and the control group was treated with experience to avoid parathyroid injury.The operation time,intraoperative blood loss,postoperative hospital stay were compared between the two groups.The levels of serum calcium ion and parathyroid hormone(PTH)were collected before and after surgery in the two groups.And the number of lymph node clearance,lymph node metastasis rate,recurrent nerve injury,parathyroid injury/misincision rate,recurrence rate and metastasis rate were compared between the two groups.Results The operation time of the observation group was(130.96±20.64)min,which was significantly less than that of the control group[(162.40±14.21)min],and the difference was statistically significant(P<0.05);there were no statistically significant differences in intraoperative blood loss and post-operative hospital stay between the two groups(P>0.05).After operation,the levels of serum calcium and PTH in the observation group were(2.31±0.10)mmol/L and(21.55±5.33)pg/mL,which were significantly higher than those in the control group[(2.03±0.11)mmol/L,(13.55±4.63)pg/mL],and the differences were statistically significant(P<0.05).The number of lymph node clearance in the observation group was(7.96±1.44)pieces,significantly higher than that in the control group[(6.52±1.32)pieces],and the difference was statistically significant(P<0.05);but there was no statistically significant difference in lymph node metastasis rate between the two groups(P>0.05).The incidence rates of recurrent laryngeal nerve injury and parathyroid gland injury/misincision in the observation group were 4.00%and 2.00%,which were significantly lower than those in the control group(20.00%and 22.00%),and the differences were statistically significant(P<0.05).The recurrence rate in the observation group was 4.00%,which was significantly lower than that in the control group(26.00%),and the difference was statistically significant(P<0.05).Conclusion The application of nano-carbon technology in thyroid cancer surgery can short-en the operation time,has certain advantages in maintaining the stability of serum calcium and PTH levels,reduce the incidence of recurrent laryn-geal nerve injury and parathyroid injury/misresection,and reduce the recurrence rate,showing certain advantages and protective effects on parathy-roid gland.