The paper presents the mathematical model of the microplasma process in an electrolyte solution and the main equation of the nanostructured nonmetallic inorganic coating growth during the coating formation on the material surface under conditions of the high energy localization in interfacial nanolayers. The microplasma process is considered as a microplasma collective discharge. The proposed physicochemical model links the main parameters of electrochemical and microplasma processes (concentration, temperature, polarization voltage, pulse duration, time of microplasma treatment) in electrolyte solutions with the parameters of the coating synthesis (growth rate, thickness, grain size). The total microplasma discharge current is limited by the current passing through the nonmixed interlayer.