Abstract: Regression analysis technique was used to measure the fecal phosphorus (P) endogenous outputs and true P digestibility values with peanut meal and soybean meal in this study with growing pigs. Six Yorkshire×Landrace barrows, with average initial body weight of (24.8±1.42) kg, were fed in the metabolic cage. According to a 6×6 Latin square design, the six diets with soybean-cornstarch-glucose based experimental diet with peanut meal containing six P level (0.09%，0.17%，0.26%，0.35%，0.43%，0.53%) were formulated, in which the peanut meal and soybean meal were the only P source. Chromic oxide (0.35%) was included in the diets as digestibility marker. Each experimental period lasted 8 d with 6 d adaptation and 2 d collection of the feces.The results showed that the P endogenous outputs were 0.526 6 g/kg DMI, true P digestibility with peanut meal was 28.00%, and true P digestibility with soybean was 38.87% with regression analysis technique.