System development of thermodynamic analysis of processes in liquid metal is the purpose of this work. It allows full enough and thermodynamically correctly describe the phenomena occurring for the interaction process in metal melts with complex composition and complex equilibrium (non-metallic and intermetallic) phases for various states of matter. The developed analysis system is based on calculating coordinates of the surface of components solubility in the metal melts. These are special multicomponent phase diagram, which allows to tie the microchanges in the metal alloy in accordance with the qualitative change in the composition of the complex phases. The general principles of the constructing method of the diagrams for different groups of metals were formulated and the diagrams of systems based on Cu, Co, Ni, Al, Pb, Bi and Sn for a wide range of composition and temperatures is plotted. Simultaneously with the thermodynamic modeling the extensive experimental study of the results interaction between the components of metallic melts was carried out. A modification method based on a study of the composition, size and shape of inclusions substances formed in the liquid metal in a concentration gradient of impurities was used. Regimes implementation options proposed methodology of the study have been substantiated. The effectiveness of the method of analysis, its prospects and its productivity to improve the processes of non-ferrous metallurgy was demonstrated.