Abstract: The glass-transition behavior of Pd₄₀Cu₃₀Ni₁₀P₂₀ bulk metallic glass was investigated by differential scanning calorimetry (DSC) and X-ray powder diffraction (XRD). The effect of pressure on the crystallization behavior of Pd₄₀Cu₃₀Ni₁₀P₂₀ bulk glass was studied by in situ high-pressure and high-temperature X-ray powder diffraction using synchrotron radiation. Phase analyses show at least six crystalline phases in the crystallized sample, namely, monoclinic, tetragonal CuaPd-like, rhombohedral, fcc-Ni₂Pd₂P, fcc-(Ni, Pd) solid solution, and body-centered tetragonal (bct) NiaP-like phases. The onset crystallization temperature increases with pressure having a slope of 1 1 K/GPa in the range of 0 to 4 GPa. The results are attributed to the competing process between the thermodynamic potential barrier and the diffusion activation energy under pressure.