Osteoporosis, a skeletal disorder of low bone density and disrupted bone architecture leading to fractures, is a common and costly condition among postmenopausal women. The biomechanical properties of bone are determined by the amount and quality of bone material and the arrangement of the material in space, mainly affected by the bone cortex, trabecular bone and collagen. When osteoporosis occurs, the cortex, trabecular bone and collagen all have the corresponding changes, which lead to the changes in biomechanical properties of bone. In this review, the changes of bone cortex, trabecular and collagen are summarized, to provide the comprehensive understanding about the changes of bone biomechanical properties in osteoporosis.