Objective The aim of this study was to explore the effect of low density lipoprotein ( LDL) on the proliferation and differentiation of MC3T3-E1 osteoblasts, as well as the expression of low density lipoprotein receptor-related protein 5(LRP5) and dickkopf-1(DKK1) mRNA of MC3T3-E1 osteoblasts. The possible mechanisms of the treatment of atorvastatin on LDL expression in MC3T3-E1 osteoblasts were also investigated. Methods Proliferation, osteocalcin expression, LRP5, and expression of DKK1 mRNA of MC3T3-E1 with interaction of LDL at 0. 05, 0. 10, 0. 20 mg/ml levels after 24 h, 48 h, 72 h were detected by CCK8, ELISA, and fluorescence quantitative PCR. Furthermore, proliferation, osteocalcin expression, LRP5 and DKK1 mRNA of MC3T3-E1 after the treatment of atorvastatin of 10-6 mol/L and 10-5 mol/L were also be studied, respectively. Results The effect of LDL on proliferation, expression of osteocalcin and expression of LRP5 and DKK1 mRNA in MC3T3-E1 osteoblasts was the most obvious under LDL with 0. 20 mg/ml level. Under that level, atorvastatin (10-6 mol/L or 10-5 mol/L) was able to make the proliferation of MC3T3-E1 osteoblasts in 48 h and 72 h be decreased, while significantly caused upregulation of osteocalcin, LRP5 mRNA expression; and down regulated DKK1 mRNA expression ( all P<0. 05). Conclusions Atorvastatin can reduce the inhibitory effect of LDL on the proliferation and differentiation of osteoblasts. The mechanisms of atorvastatin on osteoblasts are possibly related to the osteoblast proliferation and expression of LRP5 mRNA and DKK1 mRNA of osteoblasts of wnt signal pathway.