The embodiment of the invention discloses a reservation method applied to a door control system as well as a mobile terminal and the door control system. The reservation method applied to the door control system comprises the following steps that the mobile terminal receives a reservation request transmitted by a reservation terminal, and confirms the reservation request; if the reservation request is agreed, the mobile terminal transmits first verification information to the reservation terminal, wherein the first verification information comprises a first door control secret key and a validity duration; the mobile terminal receives a video connection request established after the door control system successfully verifies the reservation terminal, and acquires a video shot by a webcam of the door control system; the mobile terminal transmits a door opening instruction to the door control system after the video is confirmed. The embodiment of the invention also discloses the mobile terminal and the door control system. According to the technical scheme of the embodiment in the invention, remote visual intercom and door opening are favorably realized; meanwhile, harassment connection is stopped, and home safety of households is guaranteed.