The study evaluates efficacy and safety of recombinant human parathyroid hormone (1-34) [rhPTH (1-34)] and alendronate (ALN) in the treatment of postmenopausal osteoporosis.Totally 65 postmenopausal women with osteoporosis were divided into 2 groups. PTH group received daily subcutaneous injection of rhPTH (1-34), and ALN group were treated orally with ALN per week. Bone mineral density (BMD) of lumbar spine (1-4), femoral neck, and total hip, serum levels of calcium, phosphorus, total cholesterol, triglyceride, alkaline phosphatase (ALP), N-terminal propeptide of type I collagen (PINP), and C-telopeptide of type I collagen (CTX) were tested before treatment and at week 24 and 48 after treatment. Serum levels of vascular endothelial growth factor (VEGF) and platelet-derived growth factor-BB (PDGF-BB) were measured before treatment and at week 48 after treatment.The rhPTH (1-34) increased BMD of lumbar spine (1-4), but decreased BMD of femoral neck and total hip at week 48 after treatment. By contrast, ALN enhanced BMD of lumbar spine (1-4) and femoral neck, but reduced BMD of total hip at week 48 after treatment. In PTH group, serum levels of PINP, ALP, and β-CTX were significantly elevated above baseline at week 24 and 48 after treatment. Treatment with ALN decreased levels of PINP, ALP, and β-CTX compared with baseline at week 24 and 48 after treatment. rhPTH (1-34) and ALN significantly decreased levels of PDGF-BB, but not levels of VEGF. rhPTH (1-34) increased levels of calcium, phosphorus and triglyceride, but decreased levels of total cholesterol. ALN increased levels of calcium and triglyceride, but reduced levels of phosphorus and total cholesterol. rhPTH (1-34) and ALN were safe in the treatment of postmenopausal osteoporosis.The study demonstrates that efficacy of rhPTH (1-34) on BMD of lumbar spine (1-4) is similar to that of alendronate in the treatment of postmenopausal osteoporosis. The effect of rhPTH (1-34) on BMD of femoral neck or total hip is weaker than that of ALN. In addition, rhPTH (1-34) increases BMD of lumbar spine (1-4) maybe by raising serum levels of VEGF, but reduces BMD of femoral neck and total hip maybe by decreasing serum levels of PDGF-BB.