Ossification of posterior longitudinal ligament (OPLL) is a common disease in Asian countries. Osteoblast differentiation in posterior longitudinal ligamentous fibroblast is a pathologic basis of OPLL. Nowadays, an effective pharmacotherapy for OPLL is still hunted for. YQHYRJ Recipe (YQHYRJ) is designed based on traditional Chinese medicine (TCM) theories, and previous clinic trials reported its effect on relieving syndromes of cervical spondylopathy. To clarify the YQHYRJ effect of OPLL on a cellular level, we induced mice fibroblasts from posterior longitudinal ligaments to differentiate into osteoblasts by human recombinant BMP-2, and treated them with YQHYRJ and its three sub-compounds: YQ, HY and RJ. YQHYRJ and the sub-compounds reduced the increase of fibroblast proliferation, mineralization, type I collagen secretion induced by BMP-2 via MTT, alizarin red staining and immunochemical examination. Moreover, these agents inhibited BMP-2 induced upregulation of ossification-related genes ALP, Col I and OC as well as BMP signal molecules Smad1, Smad 5 and Runx2 mRNA expression. These results suggested YQHYRJ to be effective in inhibiting osteoblast differentiation induced by BMP-2 in fibroblasts from posterior longitudinal ligament. YQHYRJ might be a promising medicine for preventing OPLL disease.