An electronic system, and a method and an apparatus for saving data of the electronic system are provided. The electrical system includes a central processing unit (CPU), a temperature sensor, a first controller, a second controller, a first storage device and a second storage device. When the CPU enters a suspend mode and the first controller detects a temperature of the electronic system to be lower than a threshold value through the temperature sensor, the second controller notify the application program to trigger the CPU to enter a hibernation mode, and operation data is moved from the first storage device to the second storage device.