Objective To study the apparent intestinal absorption and true intestinal absorption for calcium and phosphorus in different dietary levels of calcium and phosphorus as well as the requirement of calcium and phosphorus by adult laboratory beagal dogs.Method Digestive test and nitrogen balance test were applied. Results Calcium excretion in feces increased obviously and the quantities of calcium absorption were no significantly different when dietary calcium level ranged from 0.52% to 1.02%. Phosphorus excretion in feces increased obviously and the quantities of phosphorus absorption were no significantly different when dietary phosphorus level ranged from 0.39% to 0.87% except 0.39%. There was a positive calcium and phosphorus balance in all test groups. Conclusion 0.52% dietary calcium level and 0.39% dietary phosphorus level are optimal for adult beagle dogs.