Modeling and performance study of large parabolic trough solar power plant using molten slat storage tank is conducted and presented for three different locations in Egypt (Aswan, Al-Arish and Hurghada) using 16 h storage system. The simulation algorithm and solar modeling have been created and simulated by MATLAB/ SIMULINK program.Acomparison between studied cities is introduced to select the best location for constructing the solar plant based on selection criteria; hot header outlet temperature, volume (hot and cold) variations during charging and discharging, and cycle power efficiency. A full design of the thermal power plant with the storage tanks is also conducted using a molten salt (60% NaNO3 and 40% KNO3). Moreover, hourly electricity plant output to obtain the influence of the thermal storage tank on the plant performance was calculated and presented. The results indicated that Aswan city is the optimum location to construct a 500 MW solar power plant under the Egyptian climate. A comparison for current model validation between simulated results and the actual results of existing plant (Archimede) was fulfilled and good agreement was obtained by maximum error 5%.