The corrosion testing system is scientifically and practically critical for corrosion testing and simulations. The main content of this work include the design and assessment of a flowing fluid cell loop (FFCL) system which was designed to test the corrosion/anticorrosion situation under simulated flowing conditions. Compared with flat cell and rotating cylinder systems which are widely used in academic lab for research purpose the testing environment in a this large flow loop could be more close to the actual situation in oil and gas industry. Two main part will be reported: in the first part the flow loop will be detailed designed and introduced. The finished flow loop will at least meet the requirements of producing turbulent fluid flow and working at acid conditions. In the second part the corrosion process of carbon steel specimen at different flowing conditions will be studied. The corrosion inhibition effect of selected chemical compounds will also be tested. The corrosion behaviors of the carbon steel specimen under different testing conditions were qualitatively characterized by impedance spectrum and other electrochemical testing methods. Surface analysis techniques such as Scanning Electron Microscopy (SEM) and 3D Optical Microscope were also used to characterize the surface morphologies changes qualitatively and quantitatively.