By using a solid-core fused silica light guide of a large numerical aperture, high power solar energy can be transmitted economically to a convenient place outside the focal area of a primary parabolic concentrator. The light flux distribution at the focal phase was firstly measured and the intercept factors of angle dependence were calculated individually for the light guides of 2, 4, 5.8, 7.3, 10, 12 and 14 mm diameters. By taking into account the influence of the loss dependence ηg(Φi) on incident angled, a simple model for the efficiency calculation of the whole system was introduced. The light guides were placed separately at the focus of the primary concentrator and the output powers of 50, 206, 374, 506, 690, 770 and 818W were successfully measured, attaining the transmission efficiency of 65 percent for the light guided of 14mm diameter. In length dependence loss measurement, the attention of -1.87 dB/m was found. The transmission property of a curved light guide was also tested, showing no significant loss in output power. The utilization of high power solar energy inside rooms or other thermally insulated places can therefore be expected. A novel light guide with an angular transformed input end was also put forward at the end. The input rays of large angles were transformed into the output rays of small angles by the angular transformed polished direction on a light guide. Both high transmission efficiency and high output power were achieved.