According to the north biggest effect of heparin subcutaneous injection time is 3 ~ 5 h, duration of 24 h, bioavailability of 92%, depending on the activity of anticoagulant factors Ⅹ a. Animal studies have shown that enoxaparin sodium accumulates selectively in the kidney, liver, and spleen, with a distribution volume (Vd) of 6 ~ 7L/kg. The average half-life was 4.5h (3 ~ 6h), and the average half-life was 6 ~ 7h for the elderly. The kidney is the primary pathway of enoxaparin sodium excretion, mainly through glomerular filtration.