Abstract: The phase transformation in the asquenched and aged Au7Cu5Al4 alloys were investigated by internal friction technique. The results show that Ms temperatures of the asquenched and aged Au7Cu5Al4 alloys are -2.7 °C and 13.8 °C, respectively. The boundary relaxation activation energy for the quenched and aged Au7Cu5Al4 alloys were calculated for 131.5 kJ/mol and 93.0 kJ/mol, respectively, which indicates the difference of ordering states of the parent phases resulted by different thermal history. By high temperature internal friction measurement it is found that the B2→L21 ordering transition is interrupted by quenching and the parent phase state of quenched Au7Cu5Al4 alloy shows B2 ordering, which suppresses martensitic transformation.