The invention relates to a method of adjusting volume of a loudspeaker in a home theater system which is connected with a plurality of loudspeakers. If users choose automatically set mode of the loudspeaker to indicate the picture frame of loudspeaker volume setting information and the setting information input to the volume of the loudspeaker, such as time slot, week, time and volumes of various loudspeakers. After being stored in the form of project file, the setting information of volume of the loudspeaker in various project files which are restored is compared with the present vision, and the setting information of volume of the loudspeaker which is consistent with the present vision is output. According to the setting information of volume of the loudspeaker, the invention adjusts the volume and the equalizer of every loudspeaker, which ensures that audio output of the loudspeaker can automatically adjust according to the set volume information of the set loudspeaker even without other complicated operation, thus providing more convenience for users.