In this article, we report a theoretical modelling of non-imaging focusing (NIF) heliostat for the application in the solar furnace system. The relationship between simulation time and the number of rays to be traced in the theoretical modelling is also presented. For this study, we would analyze several important parameters to affect the maximum solar concentration ratio of non-imaging solar furnace system and explore how the non-imaging solar furnace achieves the theoretical limit of solar concentration ratio by excluding the practical imperfection factors. As case study, we consider non-imaging solar furnace system consisted of a NIF heliostat with 5 × 5 facet mirrors with the dimension of 100 cm × 100 cm each and a secondary parabolic concentrator with a focal length of 30 cm. The solar concentration ratios were simulated for different target distance in which the maximum solar concentration ratios were obtained as 14,753 suns, 30,214 suns, 40,059 suns and 44,209 suns for the target distances 25 m, 50 m, 75 m and 100 m respectively.