1990, went to Europe and Belgium for further study. From 1995, he obtained the doctor's degree in Otolaryngology from the Affiliated Hospital of Ghent University, Belgium, and the best doctoral thesis. After that, he continued to do postdoctoral and clinical research at Ghent University. /kloc-returned to Shanghai Second Medical University at the end of September, 1999, and worked in Shanghai Children's Medical Center affiliated to Shanghai Second Medical University as an associate professor, deputy chief physician and tutor for master students, responsible for the clinical and scientific research work of otolaryngology and hearing center. He is currently the director of the Department of Otolaryngology of the Pediatric Hospital affiliated to Fudan University in Shanghai, and the director of the Shanghai Children's Hearing Impairment Diagnosis and Treatment Center.

Dr. Xu is mainly engaged in otology research and the diagnosis and treatment of snoring in children. During his study and work in Belgium, he was funded by the National Natural Science Foundation of Belgium and did a lot of clinical audiological research, especially the advanced objective audiological detection method with frequency characteristics. This research work has important clinical value for the early prevention and treatment of deafness. The research results have been published in international professional otolaryngology journals and audiology journals 16 articles. MEDLINE included 7 articles and international SCI included 5 articles.

After returning to China, Dr. Xu continued to engage in clinical work and audiological research in otolaryngology, and was funded by the Fund for Returned Overseas Students of the Ministry of Education and the Shanghai Science and Technology Commission. Recently, it was awarded a scientific research project by the Municipal Health Bureau to study the prevention of deaf children. Take the lead in carrying out newborn hearing screening-diagnosis-intervention in China, so that more than 2,000 cases of newborn hearing screening in this city have been diagnosed clearly, with a coincidence rate of 100%, and timely intervention and rehabilitation have been carried out. This mode of work has been introduced and popularized one by one in all provinces and cities in China, so as to achieve early detection and early treatment. The results of this research have published 8 papers in professional otolaryngology journals and audiology journals at home and abroad, including Research on Newborn Hearing Screening Technology, Shanghai Experience of Newborn Hearing Screening, Objective Hearing Assessment for Deaf Children, Cochlear Implantation for Deaf Children, etc. And won the first prize of Shanghai Science and Technology Progress Award in 2004 together with the Municipal Health Bureau. Participate in 16 international professional academic conference, and read out four papers at the international academic conference with the first author 14. Successfully organized and held the International Conference on Audiology and the National Conference on Early Diagnosis and Intervention of Hearing Impairment in Children.