The invention relates to a method and device for analyzing breakdown characteristics of an insulating medium under oscillation type impulse voltage. The method comprises the following steps: carrying out breakdown tests by adopting oscillation type impulse voltage signals with the same characteristics for preset times; recording a breakdown signal generated when the insulating medium is subjected to breakdown under the wave form of the oscillation type impulse voltage in each breakdown test; determining the oscillation periods of the oscillation type impulse voltage signals according to the oscillation frequencies of the oscillation type impulse voltage signals and determining the duration of each oscillation period; performing statistics to determine the total breakdown times in all breakdown tests according to the recorded breakdown signal and calculating breakdown times within each oscillation period according to the duration of the corresponding oscillation period; determining the breakdown probability of each oscillation period according to the breakdown times of each oscillation period and the total breakdown times; forming an oscillation period discharge probability curve according to the number of the oscillation periods and the breakdown probability of each oscillation period. With the adoption of the scheme of the embodiment of the invention, the influence of the oscillation type impulse voltage on the insulating medium can be effectively analyzed.