Coronary artery disease (CAD) is stated as one of the most common causes of death all over the world. This article explores the influence of multi stenosis in a flexible and rigid left coronary artery (LCA) model using a multiphase blood flow system which has not yet been studied. Two-way fluid–solid interaction (FSI) is employed to achieve flow within the flexible artery model. A realistic three-dimensional model of multi-stenosed LCA was reconstructed based on computerized tomography (CT) images. The fluid domain was solved using a finite volume-based commercial software (FLUENT 2020). The fluid (blood) and solid (wall) domains were fully coupled by using the ANSYS Fluid-Structure Interaction solver. The maximum pressure drops, and wall shear stress was determined across the sever stenosis (90% AS). The higher region of displacement occurs at the pre-stenosis area compared to the other area of the left coronary artery model. An increase in blood flow velocity across the restricted regions (stenosis) in the LCA was observed, whereas the recirculation zone at the post-stenosis and bifurcation regions was noted. An overestimation of hemodynamic descriptors for the rigid models was found as compared to the FSI models.