An experiment on metabolism of endogenous nitrogen and endogenous amino acids was carried out to ascertain the maintenance requirements of protein and amino acids for Guizhou Xiang pigs breed. Six castrated Congjiang Xiang pigs and 6 castrated Jianbai Xiang pigs at the age of 3.5 to 4 months and body weight of (12±2) kg with the same genetic background were selected, and nitrogen free diet (NFD) and NFD+5% enzyme-hydrolyzed casin (EHC) methods were adopted in this study. It showed the metabolic rule of endogenous nitrogen was 0.212 g/d W^0.75 and that of endogenous amino acids was 1.463 g/d W^0.75. The results indicate that the maintenance requirement of digestible crude protein (DCP) is 1.91 g/d W0.75, and that of amino acid (AA) is 2.10 g/d W^0.75 for Guizhou Xiang pigs. The AA model (Lys as 100) is: Thr 54, Val 188, Met 40, Ile 79, Leu 126, Phe 101, Lys 100, His 25, Arg 58 and Trp 17.［Chinese Journal of Animal Nutrition, 2010，22（6）:1523-1528］