The femoral biomechanical properties, bone mineral density (BMD), contents of calcium (Ca), phosphorus (P) and alkaline phosphatase (ALP) and bone turnover markers in rats, as well as viability, cycle and apoptosis of osteoblasts and ALP activity in osteoblasts were measured in the ovariectomized rats so as to explore the functional significance of ERK-5 in postmenopausal osteoporosis. The gene discussed is MAPK7; the disease is postmenopausal osteoporosis.