Père David's deer (Elaphurus davidianus), a unique species of deer in China, the population has recovered to more than 10000 in the world after more than 100 years of efforts. It seems that there is no danger of extinction due to the high levels of inbreeding in the population of Père David's deer, but there are still huge concerns. By analyzing the changes, extinction, and recovery of the population of Père David's deer and the development trend of four major populations (Woburn Abbey, Nanhaizi, Dafeng and Shishou), this paper explored the multiple factors that have been disturbing the development and expansion of the population of Père David's deer in the past thousand years. The protection measures, such as placing equal emphasis on population protection and habitat protection and strengthening disease monitoring, were put forward to provide reference for Père David's deer and other large terrestrial endangered mammals to break through the bottleneck of population development.