Elastic and anelastic properties of Zr 5 5 Al 1 0 Ni 5 Cu 3 0 bulk glass have been investigated at high temperatures with the electromagnetic acoustic resonance technique within the frequency range of 300-1500 kHz. The elastic constants of as-cast sample decrease monotonically up to the glass transition temperature T g and jump up just above T g , but such jumps disappear in the cooling and subsequent heating processes. This indicates that an irreversible structural stabilization occurs at T g under ultrasound vibration. As for ultrasonic attenuation, prominent peaks appear at T g in the first heating process. These attenuation peaks can be attributed to the atom movements in the initial glassy state.