Surge protection circuit of video input signal

The invention discloses a surge protection circuit of a video input signal, comprising a capacitor C1, a discharge tube T1 and three resistors R1, R2 and R3, wherein the resistor R1, the resistor R3 and the coupling capacitor C1 are connected to a video input circuit in series; one end of the discharge tube T1 is connected with a video input line at the front end of the resistor R1, and the other end of the discharge tube T1 is grounded; and one end of the resistor R2 is connected with the back end of the resistor R1 and the other end of the resistor R2 is grounded. The surge protection circuit can protect video AD devices at the same time of not influencing signal quality and avoids the devices from being burnt due to surge impact. The surge protection circuit is provided with one discharge tube and four capacitance resistance elements, and the structure is simple.