Bulk metallic glasses have unique mechanical properties, including high strengths (~2 GPa), large elastic limits (2%~3%), and excellent resistance to corrosion, but the poor room temperature ductility restricts its applications as structural materials. In this paper, the room temperature brittleness of bulk metallic glasses was discussed based on the deformation and fracture mechanism, and the progress in improving room temperature ductility by introducing second phase in the amorphous matrix was summarized.