Concentrated Solar Radiation flux mapping is one of the most important and critical exercises to assess the peak flux and net thermal energy of any Concentrated Solar Power (CSP) concentrator. The flux distribution analysis is important in design and performance prediction of concentrator and in design of receiver size and its material. This paper presents the comparison of experimental and numerical results of flux distribution on flat receiver carried out for small heliostat field. Here thermocouple method is used to find the flux distribution on the flat receiver due to small heliostat field. The proposed Heliostat field is designed for 100 m 2 heliostats mirror area. Initially the flux reflected from four heliostats of one row is experimentally determined by using thermocouple method. The rays reflected from the heliostat are targeted on the central flat receiver kept at 13 m from the heliostats and 2 m top from the ground. This test results provides the size of focus, the total solar radiation concentrated, peak flux, average flux, solar flux distribution within the focus area. This flux distribution is compared with the ray tracing software SolTrace. The results of the SolTrace are used to predict the flux distribution of the total heliostat field of 100 m 2 .