The study was conducted via metabolic experiment of forced feed on Linwu ducks to determine the effects of phytase (750 U/kg) supplemented to 18 kinds of feedstuffs on the utilization of calcium, phosphorus, and other nutrients. Results showed that the true utilization rate of phosphorus by the supplementation of phytase to all feedstuffs could be improved by range from 0.92% to17.29%, and among of which, to wheat middling 2, wheat bran, rice bran, and corn powder were improved 11.79% (P<0.05), 8.46% (P<0.05); 17.29% (P<0.05) and 16.33% (P<0.01) respectively, which had reached significant or very significant level. While, the utilization rate on the rest of the feedstuff's, on the contrast, were some improved, but they did not reach up to the significant level (P>0.05). The true utilization rate of calcium by supplementation of phytase to all feedstuffs could be improved by the range from 2.74% to 22.12%, furthermore, to broken rice (early), corn, wheat, wheat bran, and cotton pulp's, the utilization rate had reached the significant level (P<0.05) with the respective value of 16.37%, 17.12%, 30.75%, 21.40% and 22.12%. The improvement by the supplementation of phytase to all feedstuffs increased by over 5% except for to brown rice (late), which was only by 2.74%. The supplementation of Phytase respectively increased the true utilization rate of dry matter, crude protein, crude fat, and energy by from 0.03% to14.60%, 0.71% to 27.05%, 2.00% to 37.69% and 0.17% to 10.07%; and the efficient phosphorus improvement value for 18 feedstuffs ranged from 0.02 g/kg to 2.6 g/kg. Therefore, there were great effects by supplementation of phytase to duck feedstuffs on the enhancing utilization rate of phosphorus, calcium and other nutrients.