The progress in high-voltage capacitors is connected with using of all-film insulation. In process of fabrication of such capacitor there arise the problem of its impregnation. Analysis showed that for each polymer material it is necessary to select proper impregnating liquid. Process of wetting may be controled by means of surface active agents (surfactants) introduced into liquid. Impregnation of good quality provides high electric strength of insulation. In the case of surfactants application it can be also recieved due to change of near-electrode and bulk processes in insulation. Proper selection of surfactants can increase breakdown stress of polypropylene and polyethylene terephtalate by 3 0 4 0 % with simultaneouse increase of service life by 1...3 orders.