The purpose of this work is to determine the optical performance of a solar parabolic concentrator which was designed and realized in the Research and Technology Center of Energy in Borj Cedria Tunisia in order to improve its thermal efficiency. In this order an experimental and optical study was carried out and Photogrammetry measurement technique has been used to determine geometric errors of the solar concentrating system. Intercept factor, slope error and displacement error has been identified and analyzed. Analytical calculation of the intercept factor for parabolic reflector with a spherical receiver under Gaussian distribution along with optical efficiency has been developed and determined according to the experimental results given by the Photogrammetry technique. Obtained results showed a relevant impact of the solar concentrator optical analyze on the overall system efficiency. (C) 2015 Elsevier Ltd. All rights reserved.