It is defined that during the machining of complex surfaces in parts operating under large fluctuating loads, in critical transition areas of profile conjugate surfaces there are formed local technological concentrators of stresses contributing to formation, development of fatigue cracks and to further destruction of parts in the course of operation. Such phenomena are discovered, for instance, at high-loaded gear teeth machining, at turbine blade profile surface machining, at manufacturing large-modular tapered threads and other parts having complex profile surfaces. There are developed and introduced methods for value decrease of such stress concentrators on the basis of the application of different methods for local surface plastic deformation of a surface layer in transition areas of profiles. As a result the probability of fatigue crack formation decreased considerably and fatigue strength in parts machined increased essentially.