To provide a support to the clinical application of alendronate (Alen) on cytology, we studied the effects of Alen on the function of osteoblasts. In this experiment, we observed the influence of MG63 cell line co-incubation with Alen at concentrations of 1 x 10(-9) mol/L, 1 x 10(-7) mol/L or 1 x 10(-5) mol/L on the osteoblastic function (proliferation, cell morphology, alkali phosphatase (ALP) activity, expression of type I collagen and effect of calcium deposition). The proliferation, cell morphology, ALP activity and type I collagen synthesis of MG63 were not affected by Alen at concentration of 1 x 10(-9) mol/L and 1 x 10(-7) mol/L, but the ALP activity as well as type I collagen production were promoted at higher concentration (1 x 10(-5) mol/L). The calcium deposition of MG63 could be increased at the lower concentration (1 x 10(-9) mol/L), while it was inhibited at the higher concentration. In conclusion, Alen at low concentration can promote the mineralization ability of osteoblasts to a certain extent, and this benefits the bone formation.