The invention provides a method and a device for detecting leakage of an electric vacuum pump system. The method comprises the following steps: an accumulated operation time length of an electric vacuum pump is counted in real time in the operation process of the electric vacuum pump; when the accumulated operation time length reaches an allowed maximum working time length, the electric vacuum pump system is judged to locate in a leakage state or not according to a present vacuum degree of the electric vacuum pump system and a preset first threshold; and if the present vacuum degree is lower than the first threshold, the electric vacuum pump system is determined in the leakage state, so that the leakage of the electric vacuum pump system can be detected.