A diamino guanidine derivative as represented by formula I, wherein R1 represents methyl, ethyl, isopropyl, n-butyl, n-propyl, n-pentyl, n-octyl, n-tetradecyl, secbutyl, 3-pentyl, cyclopentyl or benzyl. When first using the compound in feeding experiments it was found that, applied to ducks, productivity was clearly improved. With similar feeding experiments, productivity of pigs and chickens was also improved. The diamino guanidine derivative can be used in preparing animal feed growth promoter.