A series of Dy(Gd)-based bulk metallic glasses with small atoms of B and N were prepared by casting the melt ingots into a water-cooled copper mould. Their phase structure was analyzed by X-ray diffraction. The glass transition and crystallization behavior were measured by differential scanning calorimetry (DSC). Kinetics parameters of crystallization such as crystallization activation energy, frequency factor and crystallization rate constant were calculated by Kissinger equation and Arrehenius law. The results show that for the Dy31Gd25Co20Al24 alloy with addition of small atoms of B and N, the crystallization model changed; both the supercooled liquid region and crystallization activation energy were first decreased and then increased; with added B atom, crystallization rate constant of the alloy was first increased and then decreased; while with added N atom, crystallization rate constant was first decreased and then increased.