Objective: To explore chemical component changes of dog bone at different lengthening time and in different bone regions of interest, and to evaluate the mineralization during Ilizarov lengthening process. Methods: The ash weight, the concentrations of calcium, phosphorus and the calcium/phosphorus ratio were measured at different intervals (2, 4, 6, 8, 12 weeks) since lengthening and the lengthened part was compared with a control area at each interval. Results: The ash weight, the concentrations of calcium and phosphorus in the lengthened area differed at all development time. The calcium/phosphorus (Ca/P) ratio in the lengthened region remained significantly lower than that in the control region up to 12 weeks after the lengthening. Conclusions: These results suggest that also other inorganic ions play an important role in the mineralization process and that they become relatively more important since 8 weeks after the lengthening. Objective: To explore chemical component changes of dog bone at different lengthening time and in different bone regions of interest, and to evaluate the mineralization during Ilizarov lengthening process. Methods: The ash weight, the concentrations of calcium, phosphorus and the calcium / phosphorus ratio were measured at different intervals (2, 4, 6, 8, 12 weeks) since lengthening and the lengthened part was compared with a control area at each interval. Results: The ash weight, the concentrations of calcium and phosphorus in the lengthened area differed at all development time. The calcium / phosphorus (Ca / P) ratio in the lengthened region was significantly lower than that in the control region up to 12 weeks after the lengthening. Conclusions: These results suggest that also other inorganic ions play an important role in the mineralization process and that that became more more important since 8 weeks after the lengthening