There is a deep conviction that the generation of the action potentialis one of the most fundamental biological activities. According to themembrane theory, active ion transport and its flow variations across theplasma membrane are responsible for generating the action potential.However, in contrast to the living model, an in vitro model based on theadsorption-desorption process of ions could equally well explain the gen-eration of the action potential. The authors constructed such a modeland mathematically related it using the stochastic differential equation(SDE). This SDE model is consistent with the kinetics of the reactionand explains the generation of the action potential. Therefore, it is phys-iologically important to re-examine the mechanism of action potentialgeneration from the perspective of the ion adsorption-desorption model.