This study was conducted to expand the application of Cornell net carbohydrate and protein system (CNCPS) to enrich the nutrient database of feeds common used in dairy industry in the northeast of China. Twenty-seven typical feeds were collected to analyze the chemical composition, such as crude protein (CP), non-protein nitrogen (NPN), soluble crude protein (SCP), acid detergent insoluble protein (ADIP), neutral detergent insoluble protein (NDIP), acid detergent fiber (ADF), neutral detergent fiber (NDF), acid detergent lignin (ADL) and starch, according to the classification method of CNCPS. Then the contents of non-protein nitrogen (PA), rapidly degraded protein (PB1), intermediately degraded protein (PB2), slowly degraded protein (PB3), bound protein (PC), unavailable fiber (CC), available fiber (CB2), starch, pectin (CB1) and sugar (CA) were calculated respectively as the provided formula in CNCPS. The results showed that SCP/CP was the highest in whole-plant corn silage from Daqing (68.74%) and the lowest in wet brewer’s grains from Shenyang (4.12%); and apple pomace from Anshan had the very highest value of ADL/NDF (34.51%) while barley from Shenyang had the lowest value (2.46%). With respect to the true protein, soybean meal from Shenyang was in the highest level (97.07%), while whole-plant corn silage from Daqing had the lowest value (26.81%); in terms of unavailable fiber content, apple pomace from Anshan was the highest (65.01%), and corn from Qiqihar was the lowest (1.6%). The experimental results showed that the CNCPS system could measure more nutrient indices of feedstuff and reflect their digesting and absorbing metabolism in dairy cattle fully. It was suggested that the methods of CNCPS could be used in the evaluation of feedstuff of dairy cattle in the northeast agricultural region of China.［Chinese Journal of Animal Nutrition, 2010，22（1）:201-206］