A processing system and a confocal processing method for confocally emitting and receiving ultrasound. Firstly, a first driving electrical signal is generated. Then, at least one first ultrasound signal having a main frequency is emitted to a reflection position according to the first driving electrical signal. With an object at the reflection position, the first ultrasound signal is reflected to form at least one second ultrasound signal. Then, a first analyzed signal whose frequency lower than the main frequency is retrieved from the second ultrasound signal, and other signals are eliminated from the second ultrasound signal, and the first analyzed signal is converted into at least one first analogous signal. Finally, first energy of a first fixed bandwidth of the first analyzed signal is retrieved by the first analogous signal. The method stops generating the first driving electrical signal when the first energy is larger than a predetermined value.
