The present study shows the thermal modeling on AMTEC (Alkali-metal thermoelectric power generation) system by analytical 1-D simulation method. In the present study, the unique AMTEC design model which consists of an evaporator, single BASE (Beta-Alumina Solid Electrolyte) tube, condenser and artery cable wick were presented. The operating design target of the present AMTEC system were 700°C in the evaporator section, and 400°C in the condenser section for solar energy conversion. The present AMTEC system operates near 10-15 % efficiency and this can be improved with the optimum design of the system. In case of improved BASE design, the system can reach over 30% efficiency.