Wireless power transmission for Space Solar Power Satellites (SSPS) calls for extremely high accuracy in steering the microwave power beam from the satellite to earth, which can be achieved by employing retro-reflective beamforming technique. In this paper, we present a numerical analysis of the performance of retro-reflective beamforming scheme in the context of SSPS. Effects of some non-ideal factors on the forming and steering of microwave power beam are simulated. A preliminary experimental system emulating microwave power transmission of the SSPS application is constructed to demonstrate the performance of retro-reflective beamforming technique.