New methodology of analyzing the influence of self-weight structural deflection towards the power conversion loss of dense-array concentrator photovoltaic (CPV) system has been formulated. As a case study, a three-dimensional mechanical model has been created based on the 23-m(2) non-imaging dish concentrator (NIDC) prototype in which self-weight mechanical deflection and the consequent effect to the optical performance have been carried out at various elevation angles to determine the solar flux distributions. Finally, the overall power conversion of dense-array solar cells by taking into account of solar flux distribution has been simulated. For elevation angle of 60, the energy variation and solar concentration ratio variation of solar flux distribution are 3.2% and 43% respectively as compared to ideal circumstance without self-weight deflection. The resulted maximum power conversion loss is 12.4%. The influence of self-weight on NIDC has significant impact to both the image distortion and pointing error of the solar flux distribution, which is one of major reasons to deteriorate the electrical power conversion of the CPV system. (C) 2015 Elsevier Ltd. All rights reserved.