Abstract： Objective To quantify Doppler signal in subclinical hypothyroidism (SHT)patients and provide quantitative parameters with three-dimensional caor power angiography(3D-PDA) and color Doppler flow imaging(CDFI). Then analysis the relationship between the above indices and TSH, TPOAb and TGAb. Methods Thirty two patients with SHT(case group)and thirty two normal controls(control group)were examined by 3D-CPA and CDFI. Under the CDFI condition to exam Peak Systolic Velocity of Superior Thyroid Artery(PSV)and Resistive Index(RI) and Acceleration Time(AT). Meanwhile region of interested(ROI) were defined to obtain histogram and the quantification index: Mean Gray (MG) , Vascularization Index (VI) , Flow Index (FI) ,Vascularization Flow Index(VFI). Then analysis the relationship between the above indices and thyroid function parameters. Such as TSH and TPOAb. Results The difference between images of case group and control group was much significant. The quantification index MG (42 ± 4. 15), VI (18. 29 ± 1.86), FI (32 ± 2.1), VFI (9.6±0. 80) ,PSV(69. 2 ± 10. 1 cm/s) and AT(0. 072 ±0. 18 s) of case group were much higher than that of control group MG(37 ±2.65) ,VI(11. 7 ±0. 102) ,FI(24. 05 ± 1.56) and VFI(0. 33 ±0. 02) ,PSV(69.2 ± 10. 1 cm/s)and AT(0. 030 ±0. 01 s) (P ＜0. 05) ,PSV VI, Fl and VFI have positive correlation with TSH TPOAb and TGAb except RI. Conclusion 3D Color power angiography is a new good tool to assess the level of echo and blood flow quantitatively. It can provide important evidence for diagnosis and treatment of SHT.