【Abstract】 Objective To study the impacts of vitamin K on bone mineral density (BMD)，serum calcium，phosphate，bone alkaline phosphate (BALP) and Bone Glaproteinin (BGP) in disuse osteoporosis children. Methods Sixty disuse osteoporosis children were randomly divided into treatment group and control group. Control group children only took caltrate D orally daily. On this basis, observation group children took vitamin K orally daily. All the children were treated for 3 months. After treatment, we observed changes of BMD，serum calcium，phosphate，BALP and BGP. Results BMD and BGP were significantly increased (P＜005), and the higher BMD and BGP existed in treatment group (P＜005)，BALP were decreased obviously (P＜005)，and the lower BALP existed in treatment group(P＜005)．The result of serum calcium，phosphorus showed no significant change (P＞005). Conclusion Vitamin K combine with caltrate D has the better therapy effects than only caltrate D in the disuse osteoporosis children.