The paper considers the process of electrodialysis separation as one of the methods for solving problems of energy and resource conservation. It is noted that one of the factors limiting the use of electrodialysis is the lack of a mathematical description, which in turn leads to difficulties in planning the process. It is proposed to use an approach to mathematical description based on criteria equations. For this purpose, the processes occurring during electrodialysis separation are considered, their driving forces are determined. It is shown that if the processes, the driving force of which is the concentration difference, can be described using the criteria of diffusion similarity, then the processes occurring under the action of the potential difference can be described by the criteria of electrical similarity. The analysis of the possibility of the existence of such criteria is carried out. It is noted that the charge is a type of substance, and thus its transfer can be described by the mass transfer equation. Based on the series transfer equation, it is possible to obtain criteria of electrical similarity, which in the future will be decisive in the criteria equations of electro-mass transfer processes, which include electrodialysis.