Metallic melts containing Bi show a certain degree of anomalies in their physical and chemical properties. In order to facilitate computational design of novel Bi–alloys for industrial applications, the phase equilibria, phase diagrams and thermodynamics bases for Bi–Li and Bi–Na binary systems are investigated with the CALPHAD method, using reported experimental characterizations. The associate solution model is introduced to describe the thermodynamic properties of Bi–Li and Bi–Na melts, and two binary associates, e.g. BiLi3 and BiNa3, are taken into consideration. The intermetallic phases involved in such two binary systems are treated as stochiometric phases. Rhombohedral Bi, bcc Li and bcc Na are considered as phases without any solubility. The Gibbs energies of all the involved phases are formulated in this work, which can give satisfactory thermodynamic descriptions for related phase equilibria and phase diagrams.