In 46 patients with decompensated posthepatitis cirrhosis, various clinical manifestations resulted from changes of bone density were noted. The relation between the changes of bone density and the level of blood calcium, blood phosphorus and alkaline phosphatase (AKP) as well as the metabolism of vitamin D was studied. It is shown that: (1) Bone mineral content (BMC) in the cirrhosis group decreased as compared with that in a control group (P < 0.05). (2) Blood calcium and phosphorus level decreased, whereas AKP level increased significantly (P < 0.01) in the cirrhosis group. (3) When BMC decreased, blood calcium and phosphorus level also decreased significantly (P < 0.01). When the condition of cirrhosis deteriorated, these changes became more obvious. The reasons may be: (1) Disorder of vitamin D metabolism in cirrhosis. (2) Decrease of calcium absorption by intestine. (3) Nutritional disturbance. It is suggested that the occurrence of bone rarefaction in cirrhosis was due to multiple factors.