Forming conditions, control factors, alloy design methods, manufacturing principle and technology of bulk amorphous alloys are analyzed and discussed using nucleation theory. The complete and necessary conditions of bulk amorphous alloy formation are preventing inhomogeneous nucleation and restraining homogeneous nucleation. The former can be realized by controlling effectively exterior melting conditions including purification, optimum cooling medium and inert atmosphere protection, et al. The latter can be achieved by the reasonable alloy design that involve multi-components, high ratio of atom radius, large negative blending heat, composition with low melting point or low eutectic point.