Objective：To study the correlation among serum 25-（OH）D3 level and thyroid function，thyroid disease duration，size in patients with Graves disease（GD） or Graves’ ophthalmopathy（GO） or hyperthyroid heart disease. Methods：Totally 150 cases of pa－tients diagnosed with the corresponding diagnosis were selected. All the cases were divided into GD group（n=50），GO group（n=50），HHD group（n=50），and the other 50 cases of healthy people at the same age were selected as the control group（n=50）. Then all the cases were taken the morning fasting venous blood，in which the FT3 and FT4，TSH，TRAb，TPOAb，serum 25-（OH）D3 were tested. The study of 25-（OH）D3 level takes the rule of the international consensus for references：serum 25-（OH）D3 level< 20 ng/mL means vitamin D deficiency，and serum 25-（OH）D3 level 20-30 ng/mL means vitamin D is not enough，when the level ≥30 ng/mL suggests vitamin D is sufficient. All the data were analyzed by SPSS 17.0 statistical software

and the significant inspection standards is P＜0.05. Results：①Compared with the control group，serum FT3，FT4，TPOAb，TRAb levels were significantly increased（P=0.000），and TSH，25-（OH）D3 levels were significantly decreased in GD group，GO group and HHD group（P=0.000）. There was no significant difference in serum FT3，FT4，TPOAb，TRAb and TSH among GD group，GO group and HHD group（P>0.05）. Serum 25-（OH）D3 level was sig－nificantly lower in GO group and HHD group than in GD group（P=0.000），and no statistical significant difference was ob－served between GO group and HHD group（P=0.320）. ②The serum 25-（OH）D3 levels in group GO were significantly positively correlated with FT3（r=0.390，P=0.006） and FT4（r=0.40，P=0.004），but there was no statistically significant corre－lation with TSH（P>0.05）. There was no statistical correlation between the remaining groups（P>0.05）. Conclusion：The low level of 25-（OH）D3 maybe closely related with the pathogenesis of Graves disease and its complications，and the deficiency of serum 25-（OH）D3 may also be involved in the development and progression of GO and HHD.