Secondary hyperparathyroidism is a common complication of chronic renal failure, which begins in the early stages of chronic renal insufficiency and progressively worsens as renal function deteriorates. For patients with chronic renal failure, the common causes of hyperparathyroidism are as follows: 1. Hypocalcemia and hyperphosphatemia, hypocalcemia and hyperphosphatemia can lead to a decrease in the activity of renal hydroxylase and a decrease in the synthesis of dihydroxyvitamin D3, which can reduce the release of bone calcium and lower the level of calcium in the blood, leading to an increase in the secretion of PTH, and at the same time, hypophosphatemia has a direct stimulating effect on the parathyroid glands, causing an increase in the secretion of parathyroid hormone. 2, metabolic acidosis, metabolic acidosis can inhibit renal hydroxylase activity and dihydroxyvitamin D3 synthesis, and at the same time can promote the generation and secretion of PTH, aggravating hyperparathyroidism.