The relation of a thermoelectric parameters of the solid solutions based on tin telluride: SnTe-MnTe, SnTe-Cu₂Te and SnTe-In₂Te₃: Pb versus an amount of dopant impurity are investigated. The crystaloquasichemical mechanism of the solid solutions formation are proposed. Showed is that at the expense of essential decreasing of a thermal conductivity factor in the solid solutions the improvement of the basic thermoelectric parameters of the material takes place. The compositions which have a maximum values of the thermoelectric Q-factor are retrieved.