A new in vitro method using the dialysis tubing for predicting the ileal apparent digestibility (IAD) of crude protein (CP) and amino acids (AA) was proposed for pig feedstuffs. Under the laboratory condition, the procedure of the in vitro dialysis tubing method was as follows: a 1.0g sample of feedstuff was placed in a 100ml Erlenmeyer flask, 10ml hydrochloric acid (0.01M, pH=20) pepsin solution (1.0mg pepsin/ml HCl) was added, and the mixture was incubated for 4h at 37°C. Then after neutralization with 0.2M sodium hydroxide, this mixture was transferred into a prepared dialysis tubing with 40ml phosphate buffered saline (PBS) solution (0.02M NaHPO 4 , 0.02M Na 2 HPO 4 , and pH=7.6) and 10ml trypsin PBS solution (2.0mg trypsin/ml PBS) was added. Then, the open side of the dialysis tubing was tied tightly with nylon threads so that the liquid could not leak out. Finally, the dialysis tubing was put into a 1000ml coneflask which was sealed with parafilm containing 300ml dialytic liquid (PBS solution). The flask was incubated for an additional 24h at 37°C. During the incubation period, the digested CP or AA could infiltrate into the 300ml PBS solution. After the two-stage incubation, the in vitro CP and AA digestibility was calculated on the basis of the original CP and AA contents of feedstuffs and the CP and AA contents of the dialyzed solution. Linear regression equations were obtained between in vitro digestibilities and IAD of CP and AA for four feedstuffs commonly used for growing pigs (0.96<r<0.99). The results show that it is possible to predict IAD of feedstuffs using the in vitro digestibility data for growing pigs. This method is accurate, rapid, reproducible and particularly suited for the evaluation of a large number of samples under laboratory condition.