The invention provides a spark gap insulation recovery voltage detection device and a detection method thereof. The device comprises a current generation apparatus, wherein the output end of the current generation apparatus is in series connection with a controllable switch K1 and then is connected in parallel with a spark gap, and is used for outputting a current to the spark gap; a voltage generation apparatus, wherein the output end of the voltage generation apparatus is in series connection with a controllable switch K2 and then is connected in parallel with the spark gap, and is used for outputting a voltage to the spark gap; a voltage-dividing apparatus which is connected in parallel with the output end of the voltage generation apparatus, and is used for detecting the output voltage of the voltage generation apparatus; and a control circuit which is connected with the voltage generation apparatus, and is used for detecting an alternating current of the output end of the voltage generation apparatus and the output voltage of a voltage adjuster, and controlling the on/off of the voltage generation apparatus according to the alternating current and the output voltage. According to the invention, a series of effective data points can be obtained in each detection process, and the device and method reduce the detection cost, and improve the detection efficiency.