Purpose: This study was conducted to evaluate the inhibitory effect of ursolic acid from Prunella vulgaris on osteoclast differentiation. Methods: MTT-assay was performed to estimate cytotoxicity of ursolic acid from Prunella vulgaris in BMMs stimulated with M-CSF. TRAP staining, TRAP activity and Real-time PCR were performed to know the inhibitory effect on osteoclast differentiation. Actin ring formation were analysed to observe the effect of ursolic acid from Prunella vulgaris. Results: Ursolic acid from Prunella vulgaris has no cytotoxicity at the concentration of $1{mu}g/ml$ or lower. Ursolic acid decreased the number of TRAP positive cells and the expression of NFATc1 gene, c-Fos gene, TRAP and OSCAR in BMMs stimulated with RANKL. Ursolic acid restrained the formation of actin ring. Ursolic acid inhibited NF-${kappa}B$ activity by inducing degradation of p-$IkB{alpha}$. Conclusions: Ursolic acid from Prunella vulgaris has the inhibitory effect of osteoclast differentiation and bone resorption. Futher studies are needed to treat osteoporosis by usolic acid from Prunella vulgaris.