The formation and crystallization behaviors of a mechanically alloyed Al75Ni10Ti10Zr5 amorphous alloy were studied by X-ray diffraction, transmission electron microscopy, and differential scanning calorimetry in the present study. The effective activation energy of the crystallization was determined by the Kissinger and Ozawa equations, respectively. The two equations yield close results and the average activation energy is 252 +/- 13 kJ/mol. The resultant crystalline products were Al and Al3Ni, and the crystallization mechanism is two-or three-dimensional nucleation and growth controlled by the diffusion of atoms. The thermal stability of the alloy was evaluated by a continuous transformation diagram obtained by the extended Kissinger equation.