Objective To compare the hemodynamic characteristics in internal carotid artery models, which were obtained by multi-scale unidirectional and bidirectional coupling models, so as to provide references for selecting models in further studies. Methods Based on the nuclear magnetic resonance image of one patient with mild stenosis of internal carotid artery, the lumped parameter model of the circle of Willis and the three-dimensional model of internal carotid artery were constructed. Those two different multi-scale models were constructed by unidirectional and bidirectional coupling. Results With the increase of stenosis degree, the inlet and outlet blood pressure and the outlet blood flow of internal carotid artery all decreased under two kinds of coupling method. The distribution of low time average wall shear stress (TAWSS) and high oscillatory shear index (OSI) of the internal carotid artery both increased with the increase of stenosis degree under two kinds of coupling method in general. The anterior cerebral artery segment showed lower shear stress and higher OSI with bidirectional coupling in 70% stenosis, and the blood flow direction of posterior communicating artery was changed, which was significantly different from unidirectional coupling results. Conclusions At a low degree of stenosis, the result of those two kinds of coupling method were consistent in general, but there was a significant difference in 70% stenosis, and the result of bidirectional coupling was closer to physiological parameters. The research findings can be better applied to the hemodynamic study of cerebrovascular diseases.