目的：探讨佝偻病的２５羟基胆骨化醇与甲状旁腺素的相关性。方法：测定１００例佝偻病患者２５羟基胆骨化醇与甲状旁腺素浓度，并对１０例未使用ＶｉｔＤ的激期患儿肌注ＶｉｔＤ３３０万ｕ，１５ｄ及２月后复查。结果：２５ＯＨＤ３明显低于正常组，随着病情加重而降低，ＰＴＨ高于正常组，但不随着病情加重而升高。肌注ＶｉｔＤ３１５ｄ复查２５ＯＨＤ３迅速升高，２月时仍持续较高水平，而ＰＴＨ无明显变化。结论：（１）佝偻病时２５ＯＨＤ３与ＰＴＨ具有一定相关性，其发病的关键是ＶｉｔＤ３活性代谢产物缺乏引起；（２）２５ＯＨＤ３在早期诊断是一敏感指标；（３）没有必要在短期内反复多次注射大剂量ＶｉｔＤ３，以免中毒 Objective: To investigate the correlation between 25-hydroxyl cholecalciferol and parathyroid hormone in rickets. Methods: The concentrations of 25hydroxycholecalciferol and parathyroid hormone in 100 cases of rickets were determined. VitD330 000 u, 15 days and 2 months later were retrospectively studied in 10 cases of children without vitD. Results: 25  OD3 was significantly lower than the normal group, with the severity of the decline, PTH higher than the normal group, but not with the increase of the disease increased. Intravitreal VitD315d review 25  OH  D3 rapid increase in February remained high while PTH no significant change. Conclusion: (1) 25      D  D3 and PTH have a certain correlation, the key to its pathogenesis is caused by the lack of VitD3 activity metabolites; (2) 25  OD3 in the early diagnosis is a sensitive indicator; (3) It is not necessary to inject large doses of VitD3 repeatedly in the short term to avoid poisoning