A protection circuit is disclosed, applied to a display apparatus. The display apparatus includes a voltage level shifter and a plurality of clock signal lines coupled to the voltage level shifter. The protection circuit includes a plurality of switches. At least one of the switches includes a control terminal, an input terminal, and an output terminal. The control terminal is coupled to a first clock signal line in the clock signal lines. The input terminal is coupled to a second clock signal line in the clock signal lines. The control terminal determines, according to a first clock signal provided by the first clock signal line, whether to conduct the input terminal and the output terminal, and the output terminal outputs a second clock signal provided by the second clock signal line. The output terminals of the switches are coupled to a node, and when the first clock signal line and the second clock signal line are short-circuited, the first clock signal and the second clock signal are pulled down as low-level signals, and the node outputs a protection signal.