Zr41.2Ti13.8Ni10Cu12.5Be22.5 bulk amorphous alloy was prepared by arc-melting and rapid casting into a copper mould. Hydrogen charging was performed electrochemically in glycerine-phosphoric acid electrolyte. The effects of hydrogen on the crystallization process of Zr-Ti-Cu-Ni-Be bulk amorphous alloy were studied by differential scanning calorimetry (DSC), Kissinger equation and high-resolution transmission electron microscope (HRTEM). It is shown that hydrogen increases the activation energy of the glass transition and crystallization, and retards the nucleation and crystal growth. Moreover, hydrogen charging contributes to the formation of isolated crystals, resulting in the precipitation of fine and uniformly distributed nanocrystallines.