Binary nanoparticles of a copper and silver alloy are of great practical interest due to the possibility of fine-tuning their physicochemical properties by changing the composition, size, shape and structure of the nanoparticles. In the presented work, the processes of formation of the internal structure of Ag-Cu nanoparticles with a diameter of 2.0-8.0 nm during their crystallization were studied using the molecular dynamics method. The features of this process were found depending on the target chemical composition of nanoparticles, their size and the intensity of thermal energy removal. Based on the analysis of available experimental data and the results of computer modeling, it was concluded that it is possible to control the internal structure and shape of Ag-Cu nanoparticles. In particular, it was shown that as a result of crystallization of binary Ag-Cu nanoparticles from a melt, metastable states that are quite stable at room temperature are captured. Keywords: binary alloys, copper, silver, nanoparticles, structure, molecular dynamics, tight-binding.