In rooms with speech action, subjective and objective room acoustics parameters should be considered in the creation of acoustic performance. In this study, an evaluation has been made over the reverberation time for the speech action of the existing Iraq-Najaf Islamic University Alawiya Conference Hall. Within the scope of the study, the control of the reverberation time affecting the subjective and objective room acoustics parameters has been examined, the relationship between the reverberation time and the surface absorptions of the room have been examined. Reverberation time on existing situation was determined by making in situ measurements. In order to control the reverberation time of the existing hall, the materials selected according to the sound absorption coefficients have been positioned differently and alternative models have been developed. The reverberation times of the alternative models were determined using the ECOTECT v.5.20 computer simulation program used for acoustic analysis, and their geometric acoustics analysis was performed using the ray tracing method. By comparing the models, the surface absorptions have been analyzed to obtain the appropriate reverberation time in room for speech action. As a result of the study, the effects of the use of walls, ceiling and floor finishing materials and surface absorptions on the reverberation time have been evaluated within the scope of improvement for speech action in the halls with square plan, flat floor and high ceiling (min 6 m).