Projecting method, device and system

The embodiment of the invention discloses a projecting method, which comprises the following steps: a projector accesses a storage space corresponding to a user to acquire projecting data pre-stored in the storage space, wherein the storage space corresponding to the user is positioned outside the projector; and the projector converts the projecting data into a corresponding projecting signal, and projects and displays the corresponding projecting signal according to the projecting signal. By adopting the embodiment of the invention, the operation flow of the user is simplified, and the safety of the projecting data is enhanced. The embodiment of the invention also discloses a device and system for applying the method.