The invention, which relates to the technical field of vacuum degree detection, provides a vacuum degree detection apparatus of a vacuum generator of a flat sucking plate and a using method thereof. The detection apparatus comprises a detection apparatus body; and a hollow cavity is formed inside the detection apparatus body. A compression surface of the detection apparatus body covers a ventilation side surface; a plurality of through holes are formed in the compression surface; and an inter-hole communication part is formed between each two adjacent through holes. Besides, a mounting hole is formed in the detection apparatus body; and the central axis of the mounting hole passes through one of the through holes. The inside of the detection apparatus body is filled with a cushion block; a block body through hole is formed in the cushion block; and a meter rod of a negative pressure meter passes through the mounting hole and the block body through hole successively and is connected with the mounting hole and the block body through hole. When the detection apparatus is in use, after air exhaust of a vacuum generator, the ventilation side surface of the vacuum generator absorbs the detection apparatus body; the negative pressure meter displays an actual vacuum degree value; and the actual vacuum degree value is compared with a preset theoretical vacuum degree value to determine whether the cleaning degree of the vacuum generator meets a standard.