The modeling of phase diagrams is quite complicated process thus assessor has to take into account many important factors such as thermodynamic properties, crystal structure, physical properties and so on. Recently, Niu et al. proposed a thermodynamic description of the Bi-K system using quite complicated model for a liquid phase (Bi, BiK, BiK3, K). Taking into account all experimental data as well as some theoretical explanations, it seems that the model does not match physical properties of the liquid phase and could be substituted by simpler one. The short discussion about thermodynamic description of the Bi-K liquid alloy is given in this paper. (C) 2015 Elsevier B.V. All rights reserved.