To analyze the correlation between the hypothyroidism of pregnant women with mild preeclampsia and their renal injury indexes. Methods: 198 pregnant women with mild preeclampsia were selected and were divided into group A (women with normal thyroid function), group B (women with subclinical hypothyroidism), group C (women with clinical hypothyroidism), and group D (women with thyroxinemia) from February 2017 to December 2020. The indexes of thyroid function and renal function of the women in the four groups were detected, which included free triiodothyronine (FT3), free tetraiodothyronine (FT4), thyroidstimulating hormone (TSH), blood urea nitrogen (BUN), serum creatinine (Cr), urinary microalbumin (UmAlb), and urinary microalbumin/creatinine ratio (ACR). Ultrasound was used to examine the renal arterial hemodynamics indexes values, which included resistance index（RI), pulsation index（PI), and peak systolic/enddiastolic velocity（S/D). Results: The levels of BUN, Cr, UmAlb, and ACR, and the values of RI, PI, and S/D of renal artery of the women had no significant different among group C, group B, and group D, but which of the women in group C, group B, and group D were all significantly higher than those of the women in group A (P<0.05). There were no correlations between the serum TSH, FT4, FT3 of the women in group A and the levels of their BUN, Cr, UmAlb, ACR, and the RI, PI, S/D values of their renal artery (P>0.05). There was a positive correlation between the serum TSH level of the pregnant women with thyroid dysfunction and their UmAlb and ACR levels and renal artery RI value (P<0.05), the FT4 level of the pregnant women with thyroid dysfunction was negatively correlated with their UmAlb and ACR values (P<0.05), and the FT3 level of the pregnant women with thyroid dysfunction was no correlation with their UmAlb and ACR levels and renal artery RI value (P>0.05). The levels of TSH, FT4, and FT3 of the pregnant women with thyroid dysfunction was no correlation with their BUN and Cr levels, and their renal artery PI and S/D values (P>0.05). Conclusion: The pregnant women with mild preeclampsia complicating with hypothyroidism can affect their renal function. In pregnant women with hypothyroidism, the higher TSH level and the lower FT4 level, the more serious renal injury is.