An electronic device with auxiliary lighting function and an operation method thereof are provided. The electronic device includes a first body, a light-emitting module, and a processing module. The first body has a first surface. The light-emitting module is located on the first surface of the first body. The processing module is coupled to the light-emitting module, and is used to determine an operation of a first power supply mode or a second power supply mode according to a current power supply state. When the processing module is operated in the first power supply mode, the processing module dynamically adjusts an auxiliary illumination light provided by the light-emitting module according to a battery power. When the processing module is operated in the second power supply mode, the processing module dynamically adjusts the auxiliary illumination light provided by the light-emitting module according to a sensing result.