Bony tissue of an average of 13.61% of the original length was resected from the middle part of the tibia shaft in 18 adult goats. Then the ostcotomized ends were compressively fixed with the sulcared half-ring external fixator.Simultaneouly, upper metaphysiotomy to lengthen the tibia with a rate of 1.0mm/d and an average lengthening rate of 20.21% of the original length in tibia was performed. The restoration of the blood circulation and hemodynamic changes during the repair process of the lengthened area and the compressively fixed bone ends were studied with roentgenography, microvascular cast observed with scanning electron microscopy(SEM) and radioactivc microsphere measurement of regional blood flow. It was found that the time of lengthening cessation there were abundant vascular networks in the lengthened zone and paralleled to the long axis of the bone. No vascular int erruption or vessel deficient arca was seen. Thesc facts show that the newly-growing vessels in the lengthened area have the same rate of the lengthening on the condition of 1.0mm/d and were gradually converted into the Haversian system of the newly formed cortex of the lengthened area. In the 2nd week after lengthening cesseation, the vessels of the cortex of the osteotomy shortening ends could grow across the space and could anastomose with each other. The primary healing could bc observed under the well-reduction and stable compressive external fixation. The results showed that the treatment of the tibia shaft shortening ends by compressive external fixation with bony lengthening simultaneously could not obviously affect the restoration of the blood supply.