Blood-brain barrier (BBB) dysfunction is involved in the pathogenesis of contrast-induced encephalopathy (CIE), which is a rare adverse event following angiography. In this study, we observed the dynamic effect and potential mechanism of ioversol on the BBB in rats. Eighty-one healthy rats were randomly divided into a normal control group (n = 9), ioversol group (n = 36), and 0.9% NaCl group (n = 36); the latter two groups were separately subdivided into four groups based on time points after treatment (0.5, 3, 6, and 24 h) (n = 9/group). Permeability of the BBB was measured by an Evans Blue (EB) assay. Levels of the tight junction (TJ) proteins ZO-1 and occludin were determined by western blot and immunofluorescence staining. EB content increased at 3 h after the administration of ioversol via the carotid artery and reached a peak at 6 h (P < 0.05), whereas it decreased to its normal level at 24 h. Western blot and immunofluorescence staining indicated that the expression of ZO-1 in brain tissues gradually decreased to its lowest level at 3 h, and then increased gradually, but was still lower than that of the normal control group at 24 h (P < 0.05). Occludin was similar, but its lowest expression appeared at 0.5 h. This study demonstrated that the permeability of BBB in rats increased first and then decreased after ioversol was injected into the carotid artery. The mechanism may be related to altered protein expression of TJs, which are important structures in BBB. Early intervention against TJ proteins may be an effective measure to prevent and treat CIE.