This study aims at the mechanism of foveola formation in bovine trabecular bone under fatigue process and its relation with biomechanical pathogenesis of senile osteoporosis. The scanning electron microscope equipped with fatigue stage was used to observe fatigue micro injury accumulation of cancellous bone. The massive foveola formation in the laminal bone of vertical trabeculae was found in the tensile fatigue test. There existed the collagen avulsion in the foveola. The massive foveola formation was also observed in the lamina bone of the horizontal trabeculae in the compressive fatigue test. The bone collagen fibers were protracted, debound with hydroxyapatite crystal, and then avulsed under tensile and bending stresses. Finally the retraction of the avulsed collagen fibers brought on the massive formation of foveolae in lamina bone. The mechanical capacity of bone also declined greatly. We infer that the direct mineralization of avulsed collagen and foveola in lamina bone would be one of the main processes of self repair in vivo, which brings on the increase in fragility and stiffness of trabeculae of senile osteoporotic bone along with the agelong accumulation of collagen fatigue injury and foveola formation in the lamina bone.