After surgery for malignant tumor of thyroid gland, there may be damage or even absence of parathyroid glands, insufficient or no secretion of parathyroid hormone, which leads to chronic hypocalcemia, so it needs to be properly supplemented with calcium preparations for treatment. Patients with chronic hypocalcemia should firstly adjust their diet, consume more calcium-rich food such as bone broth, supplement vitamin D, and take calcium supplements such as calcium gluconate or calcium carbonate for treatment, which is more effective. After thyroid cancer surgery, it is recommended that patients can choose calcium carbonate vitamin D₃ tablets for calcium supplementation treatment. These drugs contain both vitamin D₃ and easily absorbed calcium, which is more suitable for these patients. For the treatment of calcium supplementation for patients with parathyroid deficiency after surgery for thyroid malignant tumor, the blood calcium value should be rechecked regularly.