The article presents the results on energy characteristics and the thermophysical state in the vapor-gas shell formation stage during electrolyte-plasma treatment. The vapor-gas shell formation stage is characterized by intense heating of the anode layer, a transition to undeveloped bubble boiling with high heat release capacity, boiling crisis emergence, and by a transition to the film mode with low heat release capacity. At the same time, a traditional electrochemical process occurs on the anode, which is accompanied by dissolving the surface layer. Dependences characterizing the influence of electrolyte-plasma treatment parameters on the specific power and specific energy of the vapor-gas shell formation stage are established. The obtained results allow optimizing the parameters of new effective processes of electrolyte-plasma treatment in controlled pulse modes, at which both electrochemical (vapor-gas shell formation) and electrolyte-plasma stages are realized within one pulse of millisecond duration.