Dingchang Xian, male, born in 1935. In 1956, Dingchang graduated from the Physics Department of Beijing University as a Bachelor, and start his career at Institute of Modern Physics of Chinese Academic of Science (CAS). In 1959, Dingchang visited at the Dubna Institute of Nuclear. In 1962, Dingchang did his PostDoc at Bohr Institute. He worked as a researcher in Dec 1986, and was selected as an Academician of CAS in 1991. Areas of Research: Theoretic Physics and Application of Synchrotron Radiation Achievement and Experience:In the course of building the Beijing Synchrotron Radiation Facility (BSRF), the first synchrotron radiation laboratory of its kind in China, he had made correct decisions on scientific planning, physics design and engineering design and solved a series of problems which had arisen in designing, construction, installation and adjustment, thus BSRF was successfully accomplished under his leadership. He had served as the first director of BSRF. And what’s more, in the course of its construction, he had trained a generation of personnel for SR engineering and organized the wide users for SR application. He proposed the EXAFS experiment with SR X ray photo acoustics just at the time when his overseas colleagues did and conducted theoretical study in this respect. In particle theory, he developed a method to calculate the relativistic invariant phase space, developed a cumulant variation method in lattice gauge field theory, proposed an analytical continuation method for the calculation of wave function in 4-D space-time, and achieved successes in the studies of classical gauge fields, 4-D wave function of mesons in the Straton Model and lattice gauge theory.