This is the fourth OCPA Accelerator School in its series . The first School was held in Hsinchu, Taiwan, August 3-12, 1998 , the second in Yellow Mountain, Anhui, July 18-27, 2000, the third in Singapore, July 25 to August 3, 2002. The 2004 school was canceled due to SARS . The purpose of this school is to provide the students a basic training on modern accelerators. It offers a program that is both exciting and practical. Participants are welcome from all countries and regions. Students are expected to have the equivalent of a senior undergraduate or graduate school training in physics or engineering. No prior knowledge of accelerators is required. Topics covered in the school include those encountered in the operation of existing accelerators, and those facing accelerators that are being proposed and constructed . The accelerators emphasized particularly include synchrotron radiation, high energy physics, heavy ions, and medical applications. Office hours and discussion sessions are set aside in the formal course sessions to consolidate the learning. After the introduction and consolidation of the basic topics, some advanced topics encountered in the more modern accelerators will be introduced. The focus of the fourth OCPA Accelerator School is synchrotron radiation light source.