OBJECTIVE：To discuss the inhibitory effect of lanthanum chloride on the calcification of vascular smooth muscle cells（VSMCs）induced by high phosphorus and its mechanism. METHODS ：On the basis of screening the action concentration and time of lanthanum chloride by MTT method ，human VSMCs were divided into control group （1 mmol/L phosphorus solution ）， lanthanum chloride high concentration control group （1 mmol/L phosphorus solution+ 60 μmol/L lanthanum chloride），model group （3 mmol/L phosphorus solution ），sodium chloride group （3 mmol/L phosphorus solution+ 180 μmol/L sodium chloride），nuclear factor κB（NF-κB）signaling pathway agonist+lanthanum chloride group （3 mmol/L phosphorus solution+ 1 μg/mL lipopolysaccharide+ 60 μmol/L lanthanum chloride），positive control group （3 mmol/L phosphorus solution+ 100 μmol/L sodium pyrophosphate），and lanthanum chloride low ，medium，and high concentration groups （3 mmol/L phosphorus solution+ 15，30，60 μmol/L lanthanum chloride）. Alizarin red S staining and Von Kossa staining were used to detect cell calcification in each group after treated with phosphorus solution for 6 d and relevant medicine for 2 d. Western blot assay was used to detect the protein expression of TNF-α receptor associated protein 6（TRAF6），nuclear factor κB inhibitor protein α（IκBα），NF-κB p65，bone morphogenetic protein 2 （BMP-2），smooth muscle 22 α（SM22α）and Runt related transcription factor 2（Runx2）. Real-time fluorescence quantitative polymerase chain reaction was used to detect mRNA expression of TRAF 6，IκBα，BMP-2，SM22α and Runx2. RESULTS ： Compared with control group ，no cell calcification was observed in the lanthanum chloride high concentration control group ，while obvious cell calcification and significant increase of OD value were observed in model group and sodium chloride group （P＜ 0.01）；protein and mRNA expression of TRAF 6 and BMP- 2 in cytoplasm as well as mRNA expression of Runx 2，protein expression of NF-κB p65 and Runx 2 in nucleus were significantly increased （P＜0.01）；protein and mRNA expression of IκBα and SM22α as well as protein expression of NF-κB p65 in cytoplasm were significantly decreased （P＜0.01）. Compared with model group，cell calcification was significantly improved in lanthanum chloride groups and positive control group ，while OD values were significantly reduced ；the expression levels of the above-mentioned protein and mRNA were reversed to varying degrees （P＜0.05 or P＜0.01）. Compared with lanthanum chloride high concentration group ，obvious cell calcification was observed in NF-κB signaling pathway agonist + lanthanum chloride group ，and OD value was significantly increased ；the above indexes were significantly reversed in cytoplasm and nucleus （P＜0.05 or P＜0.01）. CONCLUSIONS ：Lanthanum chloride can inhibit the calcification of VSMCs induced by high phosphorus ，and its mechanism may be related to the inhibition of NF-κB signaling pathway activation.