Uniaxial tensile and uniaxial compressive tests for Zr-based bulk metallic glasses (BMGs) were conducted at room and cryogenic temperatures, respectively. It was observed that both the change of macroscopic fracture mode from ductile shear fracture to brittle normal tensile fracture and microscopic fracture feature from micron-scaled vein patterns to nano-scaled dimples with decreasing test temperatures were identified, indicating a significant ductile-to-brittle transition (DBT) behavior. The mechanism of DBT behavior was revealed by the competition between the intrinsic critical shear strength τ0 and critical tensile strength σ0 at different temperatures.