Ge-Sb-Te chalcogenide alloys are important for applications in advanced (non-volatile) random-access memory based on a reversible switching between the crystalline and amorphous phases. As the amorphisation occurs via the liquid state, a detailed knowledge of the liquid structure is essential for understanding the glass formation. We aim to investigate the atomic structure and temperature-dependent structural changes in liquid alloys from GeTe-Sb2Te3 pseudo-binary system. The principal questions concern the local atomic ordering in the liquid phase and atomic dynamics. The atomic structure will be investigated by combining different experimental data (NDIS, XRD, EXAFS) in the framework of reverse Monte-Carlo simulation technique. Atomic dynamics will be studied by dynamic viscosity measurements and ab initio molecular dynamics calculations supported by structural data obtained.