The objective of this study was to evaluate the correlation among total phosphorus, phytate phosphorus and true availability of phosphorus in adult Cherry Valley ducks, and the regression models of true available phosphorus in common feedstuffs were established, which could provide scientific evidence for an exact feed formula in ducks. Common feedstuffs for ducks were collected from the country, and 30 feedstuffs were selected as the representative samples according to the chemical composition and variation. The contents of total phosphorus and phytate phosphorus were determined by chemical composition analysis, and true availability of phosphorus was determined by fasting-force feeding. The regression among the total phosphorus, phytate phosphorus and true available phosphorus was analyzed. The results showed that true availability of phosphorus in corn, wheat milling by-products, soybean meal, rapeseed meal and corn DDGS samples for ducks were 80.6%, 39.01%, 53.03%, 38.69% and 45.55%, respectively. Significant prediction models and high correlations were observed in corn, wheat milling by-products and soybean meal samples, and the regression equations among available phosphorus (Y), total phosphorus (X1) and phytate phosphorus (X2) were Y=0.008+1.226X1－0.595X2 (R2=0.98，RSD=0.004，P<0.05)、Y=0.047－0.148X1+0.640X2 (R2=0.77，RSD=0.060，P<0.05) and Y=－0.141+2.779X1－4.610X2 (R2=0.85，RSD=0.084，P<0.05). In conclusion, the content of true availbilal phosphorus in corn, wheat milling by-products and soybean meal can be accurately predicted by total phosphorus and phytate phosphorus.［Chinese Journal of Animal Nutrition，2011，23（2）：258-265］