Not sure. He received his doctorate in 1988, so he was called "Dr. Peng". He didn't take off the title at a specific time. He has been engaged in scientific research and venture capital, and has made outstanding contributions to China's scientific and technological innovation and social development. His achievements and influence have gone beyond a simple degree title. Dr. Peng refers to Peng Junfeng, a famous Chinese scientist, academician of China Academy of Engineering, computer scientist, artificial intelligence expert, educator, entrepreneur, investor, philanthropist and social activist.