We apply magnetohydrodynamic (MHD) modeling to the radio galaxy Hercules A for investigating the jetdriven shock, jet/lobe transition, wiggling, and magnetic field distribution associated with this source. The model consists of magnetic tower jets in a galaxy cluster environment, which has been discussed in a series of our papers. The profile of underlying ambient gas plays an imp ortant role in jet-lobe morphology. The balance between the magnetic pressure generated by axial current and the ambient gas pressure can determine the lobe radius. The jet body is confined jointly by the external press ure and gravity inside the cluster core radius Rc, while outside Rc it expands radially to form fat lobes in a steeply decreasing ambient thermal pressure gradient. The current-carrying jets are responsible for ge nerating a strong, tightly wound helical magnetic field. This magnetic configuration will be unstable against t he current-driven kink mode and it visibly grows beyond Rc where a separation between the jet forward and return currents occurs. The reversed pinch profile of global magnetic field associated with the jet and lobes pro duces projected B-vector distributions aligned with the jet flow and the lobe edge. AGN-driven shock powered b y the expanding magnetic tower jet surrounds the jet/lobe structure and heats the ambient ICM. The lobes expand subsonically; no obvious hot spots are produced at the heads of lobes. Several key features in our MHD modeling may be qualitatively supported by the observations of Hercules A. Subject headings:galaxies:individual: Hercules A — galaxies: active — galaxies: jets — methods: numerical — MHD