The invention relates to the technical field related to a series capacitor compensation device, in particular to a measurement method of the voltage division ratio of a voltage-sharing capacitor for a spark gap of the series capacitor compensation device. The method comprises the steps of disconnecting the electrical connection between a first capacitor branch circuit and a low-voltage end and/ or disconnecting the electrical connection between a second capacitor branch circuit and a high-voltage end; respectively applying the same test voltage at the two ends of the first capacitor branch circuit and the second capacitor branch circuit, and controlling the frequency of the test voltage to be more than or equal to 50Hz; measuring the current of the first capacitor branch circuit to obtain first capacitor branch circuit current, and measuring the current of the second capacitor branch circuit to obtain the second capacitor branch circuit current; taking the inverse ratio of the current ratio of the first capacitor branch circuit current and the second capacitor branch circuit current as the voltage division ratio of the first capacitor branch circuit and the second capacitor branch circuit. After the method capable of improving the test frequency is adopted, the test voltage can be reduced to be lower than the safe voltage of 50V under the condition of meeting the requirements of test current, so that the test safety is improved, and the measurement method has very high power frequency interference resistance.