In this paper, the optimal ratio of tannic acid (TA) and sodium molybdate (SM) and the influence of different hydrodynamic factors on the corrosion inhibition effect of 304 stainless steel at 90° bending were evaluated. This study combines static immersion and simulation of a pipeline circulating flow device, and uses electrochemical and computational fluid dynamics (CFD) simulations to evaluate the corrosion inhibition effect of corrosion inhibitors in this system. The optimal ratio of tannic acid and sodium molybdate is 3 g/L tannic acid +0.05 g/L sodium molybdate. The study found that the corrosion inhibition efficiency of the corrosion inhibitor at different positions of the elbow is different, and the corrosion inhibition efficiency decreases with the increase of the flow rate. The surface morphology and corrosion products of the samples were analyzed by SEM and XPS, which further verified the experimental results and analyzed the corrosion inhibition mechanism.