The acoustic transfer functions(TFs)between a sound source and receiving points represent the deep structure of acoustic systems.The impulse response of an acoustic system can be derived by inverse Fourier transform of the transfer function.In this paper,we discuss about the impulse response method of Maximum-length Sequence and show experimental results in the audiovisual room of Kure National College of Technology.Moreover,the reverbration time(RT),Rapid Speech Transmission Index(RASTI),which are important physical properties for Speech Intelligibility(SI),and the short-time spectrum were calculated from these impulse responses.The Impulse respons,RT,RASTI and short-time spectrums were also compared at three receiving points in this room.The results demonstrate that RASTI depends on both the energy ratio between direct sound from the source and time-delayed reflections(D/R)in a reverberant space.