<p>The thermodynamic calculation was used in the Cd–Nd phase diagram according to the thermodynamic rule. Based on the newly reported phase relations, the thermodynamic expression of the four solution phases (liquid, bcc, dhcp and hcp_A3) was described with the Redlich–Kister form. Four species (Cd₁₁Nd, Cd₆Nd, Cd₅₈Nd₁₃ and Cd₃Nd) were treated as stoichiometric compounds. Three intallic compounds (α-Cd₂Nd, β-Cd₂Nd, CdNd and Cd₄₅Nd₁₁), which exhibited a little homogeneity range, were treated as a two-sublattice model (Model I). Three compounds (α-Cd₂Nd, β-Cd₂Nd, CdNd and Cd₄₅Nd₁₁), with low solubility, were used as a two-sublattice thermodynamic model (Model I). The compound CdNd was simultaneously optimized with another model to cope with disorderly transitions from bcc-A2 to bcc-B2 (Model II). The prescription of (Cd, Nd)_0.5(Cd, Nd)_0.5(Va)₃ was given expression to the order structure of the CdNd phase. Fourteen different types of phase transition were raised in the Cd–Nd system.</p>