Abstract: The objective of the experiment was to determine nutrient value of corn, wheat, brown rice and cassava, and compare the ability of chickens and ducks to nutrition of the feedstuffs. According to 4×4 Latin square design, four Sanhuang Chicken, Hainan Chicken, Beijing Duck and Hainan Duck were used respectively. The results showed: The apparent metabolizable energy (AME) of corn in birds was highest, the AME of cassava in birds was lowest. The difference of AME in corn、brown rice and wheat were not significant (p>0.05). The difference of AME in Hainan Chicken and Hainan Duck between corn and cassava were significant (p≤0.05). The difference of AME in Sanhuang Chicken and Beijing Duck between corn and cassava were very significant(P≤0.01). The birds’ digestibility of crude fat and protein in corn was highest, there were no significant between corn and brown rice (p>0.05), and the difference was significant between corn and cassava (p≤0.05). The digestibility of crude fibre in brown rice in Hainan Chicken、Beijing Duck and Hainan Duck were highest, the difference between corn was significant (p≤0.05). But the difference between corn and cassava was not significant (P>0.05). There were no significant difference between chickens and ducks in AME and digestibility of four determined feedstuffs (P>0.05).