Stepped plug gauge used for detecting clearance

The invention relates to a stepped plug gauge used for detecting the clearance, which is characterized by comprising a handle, wherein each end of the handle is rotatably connected to a measuring ruler through a round pin, the two measuring rulers are of a stepped shape which is gradually thinned from a connecting end to a free end, the thickness difference between two adjacent steps located on the same measuring ruler is equal, the thickness difference between two adjacent steps located on the different measuring rulers is also equal, and the difference between the thickness of a thickest step on one of the measuring ruler and the thickness of a thinnest step on the other measuring ruler equals to the thickness difference between two adjacent steps located on the same measuring ruler. Steps on one of the measuring rulers are sequentially 5mm, 4mm, 3mm, 2mm and 1mm in thickness; and steps on the other measuring ruler are sequentially 10mm, 9mm, 8mm, 7mm and 6mm in thickness. The stepped plug gauge provided by the invention can be widely applied to clearance detection in a narrow space.