The provision of certain information regarding the surface layer of the equipment parts is one of the critical issues for the modern mechanical engineering. The development of new technologies of protective-strengthening treatment of critical parts surface requires the development of improved methods for surface layer material state assessment as a result of high-energy impact typical for ion-plasmatic, ion-implantation and combined treatment method. Moreover, the peculiarities of industrial mechanical engineering production require the development of simple and efficient methods of surface layer parameters checkout. The application of protective coatings complicates the use of universal method of the parts surface layer parameters assessment. The present article is devoted to the development and studying of a new method for the parts surface layer state assessment after its treatment of various types, including the protective-strengthening technologies and the application of protective coatings. The specific features of the proposed assessment method are its simplicity, reliability, and universality.