An electronic reader which includes a storage unit, and an input unit generating signals in response to user input. In addition, a processing unit detects the signals corresponding to the user input; controls the electronic reader to enter a reading mode, and displays a file according to the user input, records a length of duration time for which the electronic reader operates in the reading mode; determines the duration time and executes a variety of protective instructions and steps depending on the length of duration time for which the electronic reader operates in the reading mode. A control method is also provided.