1989.09- 1994.07, Ph.D. student in orthopedics, Second Military Medical University.
1996.10-1996.12 Visiting Scholar in Orthopaedics, University Hospital of Zurich, Switzerland.
2000.09-2000.6438+00 Visiting Scholar, Kansas Medical Center, USA
200 1.04-200 1.06 Visiting Scholar of Spinal Surgery, TSRH Hospital, Dallas, USA.
2002. 10-2002. 12 Visiting scholar in new york Special Surgery Hospital.
2008.11-2008.12 Visiting Scholar, Spinal Center, National University Hospital of Singapore