Objective To investigate the effects on the phenotype,especially the mineralization ability of human embryonic lung fibroblasts(HELFs) by transfection with adenovirus vector ecoding human bone morphogenetic protein-2 gene(Ad-BMP-2). Methods The HELFs were primarily cultured, then transfected with Ad-BMP-2. The morphologic characteristics of the cells were observed. The cell proliferation, alkaline phosphatase activities, BMP-2 protein expression, and the mineralization ability were detected with the methods of MTT, ALP staining, Western blot, and alizarin red S staining, respectively. Results After transfection, the shape of HELFs changed from silm spindle to multifigure, the cells became bigger than before. The colonies changed from unilaminar into multilaminar. The proliferation of HELFs was severely inhibited after transfection. An obvious BMP-2 lane was shown in Western blotting. Most cells presented positive in ALP staining, and large number of nacarat mineralized nodes were observed after alizarin red S staining. Conclusion HELFs were capable of transforming into osteoblast-like phenotype, and were endowed with the ability of mineralization while being transfected with Ad-BMP-2.