Presently, postmenopausal osteoporosis mainly caused by excessive activation of in vivo osteoclasts has become a global public health burden. Natural compounds have gradually become the potential drugs for the treatment of postmenopausal osteoporosis. Aloperine is a new alkaloid extracted from the leaves and seeds of sophora bean. The current studies have proved that aloperine has many biological activities, including anti-inflammatory, antiviral and anticancer activities. This study shows that aloperine can inhibit activity and formation of osteoclast mediated by RANKL in a dose-dependent manner without affecting the activity of bone marrow macrophages (BMM). In addition, it is found that aloperine can inhibit the expression of osteoclast specific marker genes, including nuclear factor of activated T cells cytoplasmic 1 (NFATc1), tartrate resistant acid phosphatase (TRAcP), matrix metallopeptidase 9 (MMP9), cathepsin K (Ctsk), V-ATPase d2 and calcitonin receptor. The in vitro experiment of aloperine proved that aloperine can inhibit the degradation of IkappaBalpha and the phosphorylation of P65, ERK and JNK. Additionally, aloperine improves bone loss in ovariectomized (OVX) mice by inhibiting osteoclast activity. This project proved that aloperine can affect the formation of osteoclasts by inhibiting RANKL signaling channel, and it is indicated that aloperine has the potential to be developed as a new drug for the prevention and treatment of postmenopausal osteoporosis. CI - Copyright (c) 2021. Published by Elsevier B.V.