A mobile terminal , comprising: a face information collecting device, configured to collect a face image; a memory , configured to prestore a face template; and a processor , configured to carry out following actions, comprising: when detecting a trigger event of lighting a screen of the mobile terminal, obtaining (S201) an event identifier of the trigger event; when detecting that the event identifier matches a pre-stored event identifier, turning (S202) on the face information collecting device and lighting (S202) the screen of the mobile terminal, wherein turning (S202) on the face information collecting device and lighting (S202) the screen of the mobile terminal comprises: turning (S202) on the face information collecting device and lighting (S202) the screen of the mobile terminal in parallel; detecting whether a switch for launching a preview interface is in an open state; when detecting that the switch is in the open state, displaying the preview interface on a display interface of the mobile terminal, the preview interface being configured to display the face image collected by the face information collecting device; and when detecting that the face image collected by the face information collecting device matches the pre-stored face template, performing (S203) an unlocking operation. a face information collecting device, configured to collect a face image; a memory , configured to prestore a face template; and a processor , configured to carry out following actions, comprising: when detecting a trigger event of lighting a screen of the mobile terminal, obtaining (S201) an event identifier of the trigger event; when detecting that the event identifier matches a pre-stored event identifier, turning (S202) on the face information collecting device and lighting (S202) the screen of the mobile terminal, wherein turning (S202) on the face information collecting device and lighting (S202) the screen of the mobile terminal comprises: turning (S202) on the face information collecting device and lighting (S202) the screen of the mobile terminal in parallel; detecting whether a switch for launching a preview interface is in an open state; when detecting that the switch is in the open state, displaying the preview interface on a display interface of the mobile terminal, the preview interface being configured to display the face image collected by the face information collecting device; and when detecting that the face image collected by the face information collecting device matches the pre-stored face template, performing (S203) an unlocking operation. when detecting a trigger event of lighting a screen of the mobile terminal, obtaining (S201) an event identifier of the trigger event; when detecting that the event identifier matches a pre-stored event identifier, turning (S202) on the face information collecting device and lighting (S202) the screen of the mobile terminal, wherein turning (S202) on the face information collecting device and lighting (S202) the screen of the mobile terminal comprises: turning (S202) on the face information collecting device and lighting (S202) the screen of the mobile terminal in parallel; detecting whether a switch for launching a preview interface is in an open state; when detecting that the switch is in the open state, displaying the preview interface on a display interface of the mobile terminal, the preview interface being configured to display the face image collected by the face information collecting device; and when detecting that the face image collected by the face information collecting device matches the pre-stored face template, performing (S203) an unlocking operation. <EOS>