Development of novel artificial synaptic devices, which make up the majority of neural networks, has emerged as a pivotal path to hardware realization of neuromorphic computing. An electrochemical ion synapse, also known as a three-terminal synaptic device based on electrochemical transistors, is a device that may efficiently use ions in the electrolyte layer to modify channel conductivity. By electrochemical doping and recovering ions in channel materials exhibiting redox activity, this device mimics biological synaptic properties. The advantages of the electrochemical ion synapse, which uses proton (H⁺) as the doping particle, are lower energy consumption, faster operation, and a longer cycle life among the ions that alter the channel material's conductance. This article reviews the recent research progress on proton-regulated electrochemical ion synapses, summarizes the material systems used for the channel layer and electrolyte layer of proton-regulated electrochemical ion synapses, analyzes the challenges faced by proton-regulated electrochemical ion synapses, and points out directions on their future development.