Mobile device, and screen locking and unlocking methods and systems thereof

The invention provides a mobile device, and screen locking and unlocking methods and screen locking and unlocking systems thereof. The screen locking method of the mobile device includes the following steps that the mobile device provides a preset color option interface for a user to select according to screen locking setting operation of the user; all color information selected by the user in the preset color option interface is preserved, and therefore the user can conveniently perform matching in screen unlocking. The screen unlocking method of the mobile device includes following steps that the mobile device provides a locking interface which contains the color option interface for the user to select color information of the same amount as the amount of the preserved color information from the color option interface; matching is performed between the color information selected by the user from the color option interface and the preserved color information, if all the color information selected by the user from the color option interface is matched with the preserved color information, a locking interface is unlocked, and if not, the locking interface can not be unlocked. The mobile device, and the screen locking method, the screen unlocking method, the screen locking system and the screen unlocking system thereof have the advantages of being difficult in distinguishing degree, capable of effectively improving unlocking safety, simple, and easy to use.