Following the insertion of capillary electrodes into the giant-axon cells of squid and successfully recording the action potential, the famous Hodgkin-Huxley model in the field of neuroscience was proposed, and Oxford Trinity College alumnus Alan Hodgkin and Andrew Huxley were awarded the 1963 Nobel Prize in Physiology-Medicine. To these groundbreaking discoveries, various types of transmembrane ion channels are related and form an important part of cellular signaling networks. Various ions carrying biochemical information driven by the electrochemical potential pass through the channels to achieve trans-membrane signal transduction and mutual regulation, endowing cells with profound and extraordinary information “metabolism” capabilities. Why has evolution selected cations as major mediators of trans-membrane signal transduction? How does the Nernst voltage determined by the trans-membrane concentration gradient drive the transport of ions across the membrane? This chapter discusses the relationship between ion channels and membrane potential from the perspective of structure and dynamics, the essential difference between channels and transporters, the common structural components of channels (including pore gates and filters), various gating mechanisms (including mechanosensitive gating, voltage gating, ligand gating, and temperature gating), and the phenomenon of fast and slow inactivation of ion channels and the molecular mechanisms behind them.