An electronic device and an operation mode switching method thereof are described. The operation mode switching method is applied to an electronic device that includes a display unit, and the electronic device has a first operation mode and a second operation mode. The display unit has a first light-transmittance in the first operation mode and a second light-transmittance in the second operation mode such that the first high light-transmittance is higher than the second light-transmittance. The method includes detecting to obtain a trigger event; judging whether or not the trigger event satisfies a predefined condition to get a judgment result and, when the judgment result indicates that the trigger event satisfies the predefined condition, generating a switching instruction, and according to the switching instruction, switching the electronic device between the first operation mode and the second operation mode.