Power source protection circuit and chip thereof

A power source protection circuit and a chip thereof. The power source protection circuit comprises a clamping circuit (1), a first transistor (M0) and a second transistor (M24). The clamping circuit is coupled between a power source (VDD) and a third electrode of the first transistor; a first electrode of the first transistor is coupled to the power source, and a second electrode of the first transistor is connected to the ground (GND); and a first electrode of the second transistor is coupled to the third electrode of the first transistor, a second electrode of the second transistor is coupled to the ground, and a third electrode of the second transistor is coupled to the power source. The power source protection circuit can protect the power source and the chip.