In this study, the Iterative Artificial Bee Colony Algorithm (IABCA) methodology was proposed to perform optimisation of a heliostat field for the Solar Power Tower (SPT) system. In this respect, a complete mathematical model of annual unweighted optical efficiency considering cosine losses, shadowing-blocking losses, atmospheric attenuation losses, interception losses and mirror reflectivity was developed firstly. A simple and efficient method is adopted to identify the heliostats with the highest possibility to shade or block another heliostat. The use of this method allows us to reduce the processing time of the shadowing and blocking efficiency and avoid unnecessary calculations. A case study of PS10 situated in Spain was used to validate the mathematical model and the proposed IABCA approach. The proposed IABCA maximize the annual unweighted optical efficiency. In order to evaluate the performance of the proposed approach, seasonal investigation on four different days 21 March, 21 June, 21 September, and 21 December at solar noon time was carried out. The results show that the proposed IABCA methodology boost significantly the performance of the heliostat field compared to the original PS10 layout. Percentage improvement for each studied day in terms of efficiency is 3.46%, 1.05%, 3.2%, 1.98%, respectively.