To investigate the influence of injury of nutrient artery on the blood supply of inner 2/3 of cortical and intramedullary tissue, the experiment was carried out on twenty-four rabbits. Four rabbits were killed and perfused with Chinese ink in femoral artery to survey the blood supply of intramedullary vessels. Others were received fracture on tibia and sacrificed respectively on the third, eighth, eighteenth, twenty-eighth, and forty-second days after fracture. Chinese ink was also perfused through femoral artery on those rabbits. The relative density of capillary vessels were determined. The results were as follows: when the nutrient artery was injured after fracture, blood supply to the intramedullary tissue and the inner 2/3 of cortical bone was interrupted. The intramedullary vessels were increared and dilated. During the whole course of healing of fraeture, the density of intramedullary capillary vessels were higher than normal. It was concluded that the anastomosis between the epiphysis and metaphysis was important in the reconstruction of collateral circulation in healing of fracture.