The invention relates to the technical field of mechanical automation, and discloses a demonstrator, an operating method of the demonstrator, a calculating device and a computer readable medium. The operating method of the demonstrator comprises the following steps: detecting that whether the human face exists in the set range in front of a screen of the demonstrator or not in real time; and whendetecting the human face, lighting the screen. In the operating method of the demonstrator provided by the embodiment of the invention, the demonstrator can automatically detect that whether the humanface exists in front of the screen of the demonstrator or not, if the human face is detected, that a person exists in front of the demonstrator is judged, then the screen is lighted automatically, and thus the operation of people is facilitated; therefore, the demonstrator does not need to be in the normally-lighted state, lighting can be carried out automatically according to the practical environment and the demands, so that the energy consumption can be saved, the service life of the display screen can be prolonged, meanwhile, the full automation of the lighting operation of the demonstrator is realized, and thus the user experience is improved.