The invention discloses a voltage short interruption reply method and device of a single-phase AC power supply provided for an air-conditioning system. The single-phase AC power supply goes through rectification of a rectifier circuit and then is input to a power factor correction (PFC) circuit. The method comprises the following steps: detecting a voltage input to the PFC circuit to obtain an input voltage instantaneous value, and judging whether a voltage short interruption occurs in the single-phase AC power supply according to the input voltage instantaneous value; if the voltage short-time interruption occurs according to the judgment, controlling a power switch tube in the PFC circuit to be turned off, and reducing an operation frequency of a compressor; judging whether a voltage of the single-phase AC power supply returns to normal; and, if the voltage returns to normal according to the judgment, improving the operation frequency of the compressor until a given frequency is reached, and, when the input voltage instantaneous value is less than or equal to an output end DC bus voltage of the PFC circuit, controlling the power switch tube to be turned on. So an input current when the voltage recovers is reduced, working time when the voltage interruption occurs is prolonged, and then the anti-interference ability of the system to the voltage short interruption is improved.