this experiment, in which we used breeding contrast test, choosing 250 ducks which were about 4-week-old healthy cherry valley ducks, studied the crude protein levels of 5 to 7-week-old cherry valley duck. Under the same conditions, they were fed with five kinds of feeds with different content of crude protein： feed Ⅰ, feed Ⅱ, feed Ⅲ, feed IV and feed Ⅴ The experiment shows that the crude protein level of breeding has an effect on the feed conversion ratio, feed daily intake, weight daily gain for the growth of cherry valley duck is at 18%. and diarrhea; and the best crude protein level in the feed