Abstract: The experiment results of sound absorption measurement of three sound absorption components were analyzed. It is found that static states of rotated diffuser in different angles have significant impact on the result of the measurement and a method of measuring in multiple static states of rotated diffuser is proposed. A comparison of the measurement results of locating measuring position to the corners of reverberation room and selecting measuring position according to ISO and national standard is made by using the proposed method. The mean result of both kinds of measurement locations are accordant, and less deviation can be achieved by locating measuring position to the corners of reverberation room. It is concluded that sound absorption in a reverberation room can be measured by locating less measuring position to the corners of rectangular reverberation room and changing states of rotated diffuser in different angles.