The results of thermodynamic investigation of some liquid alloys in Ga-Sb-Bi-Sn system, obtained by calculation according to different thermodynamic predicting methods, are presented in this paper. The research was done based on the known experimentally obtained thermodynamic properties of related binary and ternary subsystems. Calculated data on a Ga-Sb-Bi-Sn system include thennodynamic properties for liquid alloys at temperature of 900K in chosen sections of investigated quarternary system with molar ratios of Sn:Sb:Bi = 6:3:1; 8:1:1 and 6:13.