In order to investigate the protein degradation rule in rumen of several common feed ingredients in deer, four adult male sika deer fitted with permanent rumen cannulas were selected to estimate the protein ruminal degradability of cottonseed meal, corn germ meal, rapeseed meal, distillers’ dried grains with solubles (DDGS), corn gluten meal, corn fiber and Chinese wildrye using the nylon bag technology. The results showed as follows: protein ruminal degradability of cottonseed meal was always the highest, compared with other common feed ingredients, the difference in protein ruminal degradability at all time points was extremely significant (P<0.01). 2) The protein ruminal degradability at 48 hour in descending order was cottonseed meal, corn gluten meal, Chinese wildrye, DDGS, corn germ meal, rapeseed meal and corn fiber, and the protein ruminal dynamic degradability showed the similar change law. It is concluded that protection technology of protein bypass rumen must be used in practice to reduce waste of protein source because of high degradability of cottonseed meal; rapeseed meal is a kind of new protein supplement to develop because of its low protein ruminal degradability; corn germ meal, DDGS, corn gluten meal, corn fiber and Chinese wildrye can be used as common feed ingredients in deer production.