In a solar central receiver system, solar radiation is concentrated on a tower mounted heat exchanger (receiver) by the use of mirrors called heliostats. To compare the experimental and numerical result for getting the better Flux distribution on the solar central receiver system, a common basis of testing is desirable. This helps in the design and performance prediction of not only receiver, but also a complete system. The method consists of optical test characterization of receiver. This research presents the Focus Test on the receiver and its implementation on solar central receiver system. The test provides the size of the focus, the total solar radiation concentrated, flux distribution and concentration ratio. Result of this test gives the idea about design of receiver and choice of material. The SOLTRACE software, developed by NREL (National Renewable Energy Laboratory, United States) for the numerical work to find out the focus size and flux distribution on the receiver. By using this result with aiming point strategy in SOLTRACE software the even flux distribution and flux image size will be optimized.