The aim of this work is to study and optimize the characteristics of a solar chimney power plant (SCPP) using numerical and experimental way. The numerical simulation is performed using the commercial computational fluid dynamics (CFD) code "Ansys Fluent 17.0". An experimental setup of a SCPP is developed in the national school of engineers of Sfax, University of Sfax, Tunisia in the North Africa. The comparison between the numerical and the experimental results have shown a good agreement. The effect of the collector roof height on the solar chimney performance is performed. The local characteristics of the air flow inside the SCPP system are presented and analyzed such as; the temperature, the velocity, the pressure and the turbulence characteristics. Results confirm that the collector roof height is very influential on the optimization of the SCPP. In fact, an increase in the generated power is recorded while decreasing the collector roof height. (C) 2017 Elsevier Ltd. All rights reserved.