Solar chimney power plant (SCPP) is a promising renewable energy technology that needs policy support and market cultivation at the early stage of its development. An accurate prediction of the levelized cost of electricity (LCOE) can be used as basis for crafting effective support policies. This study presents an unsteady theoretical model that considers hourly meteorological data and soil heat storage in estimating the annual power generation of an SCPP. A cost benefit model is adopted to calculate the LCOE of a 10-MW SCPP in Yinchuan, a representative geographical location in the Northwestern region of China. By considering the cost advantage of China, the concessional loan, as well as the low operation and maintenance cost, the LCOE of the SCPP is estimated to be 0.4178 Yuan/kWh, which can compete with those of wind power and solar PV in China. This work lays a good foundation for the accurate prediction of power generation and provides a reference for the Chinese government in crafting effective support policies for SCPPs.