The invention discloses indoor light regulating equipment based on projector states. The indoor light regulating equipment comprises a projector state detecting unit, an indoor light detecting unit, aprocessing unit, a judging unit and a control unit and is characterized in that the projector state detecting unit detects whether a projector is started or not; if the projector is started, the indoor light detecting unit is started to detect indoor light intensity, indoor light intensity is processed by the processing unit, and then the processed detected data is transmitted to the judging unit; the judging unit judges whether the received detected data is in the preset working range of the projector or not; if the received detected data is not in the preset working range of the projector,the working mode of the projector is regulated through the control unit, and the control unit is used to regulate the indoor light intensity when the preset working range of the projector is not reached after the regulation until the preset working range of the projector is reached. The invention further discloses an indoor light self-adaptation regulating system and method based on projector state triggering. By the indoor light regulating equipment, system and method, the visual effect of indoor viewers can be increased effectively.