An encryption method based on a mobile terminal for a Bluetooth watch and the Bluetooth watch thereof are disclosed. The method includes: the Bluetooth watch establishing a communication connection with a mobile terminal; displaying, by a screen of the Bluetooth watch, an encrypted interface to prompt a user to enter an initial password; receiving the initial password from the user and storing the initial password in the Bluetooth watch; detecting whether the Bluetooth watch is removed by the user; hiding the instant notification message received from the mobile terminal, and displaying an unlock interface on the screen to prompt the user to enter an unlock password, when the Bluetooth watch is determined to be removed by the user; receiving the unlock password entered by the user at the unlock interface; and unlocking and displaying the instant notification message received from the mobile terminal, when the unlock password matches the encryption password.