Abstract: The pharmacokinetics of calcium in L threonate calcium is studied by radiotrace method. The results show the relationship between drug time curve, pharmacokinetics parameters and dosage are positive correlation, and calcium distributes in important tissues such as stomach, intestines, blood and bone. In 24 hours, about 40% calcium is drained in urine, 30% calcium is evacuated in feces, 10%～20% calcium deposite in blood or bone. The radiotrace method is a kind of special, sensitive, accurate method of testing calcium metabolism.