An electronic system is provided. The electronic system includes a first electronic device and a second electronic device. The first electronic device generates a new key every certain time period. The second electronic device establishes a connection with the first electronic device to receive the new key therefrom to store the new key as a latest received key. When the first electronic device receives an input event under a locked status, the first electronic device requests the second electronic device to transmit the latest received key thereto, determines that whether the latest received key is the same as the new key and switches to a power on and unlocked status automatically when the latest received key is the same s the new key.