Thermodynamic databases are essential to understanding alloy properties and guiding materials design. In this work, the mixing enthalpies of the liquid phase in the Gd-Te, Dy-Te and Ho-Te binary systems are calculated using Ab-initio Molecular Dynamics (AIMD) simulations and the thermodynamic parameters are determined using the CALculation of PHAse Diagrams (CALPHAD) method combined with the phase equilibrium data and thermodynamic data. The associated solution model is employed to describe the liquid phase of these systems. The sublattice model (Gd,Te)_0.0296(Gd)_0.4(Te)_0.5714, (Dy,Te)_0.0286(Dy)_0.4286(Te)_0.5714 and (Ho,Te)_0.5(Te)_0.5 are utilized to describe Gd₂Te₃, Dy₂Te₃ and HoTe, respectively. The line compounds, i.e. GdTe, DyTe, and DyTe₂, are modeled using the stoichiometric model. The calculated results can describe the experimental and thermodynamic information reported in the literature. In addition, the existence of a liquid-liquid separation in the Dy-rich side in the Dy-Te binary system is proposed in this work.