Device for protecting bolt

The utility model discloses a device for protecting a bolt, which comprises a protective sleeve covering the bolt, and the protective sleeve comprises a first connecting part, an extension section and a second connecting part which are sequentially connected from bottom to top; one end of each fixing part penetrates through the protective sleeve, extends into the protective sleeve and abuts against the outer surface of the bolt, a plurality of limiting strips rotationally connected with the fixing parts are annularly arranged at the positions, located in the protective sleeve, of the fixing parts, and a plurality of limiting blocks corresponding to the limiting strips one to one are fixedly arranged on the inner wall of the protective sleeve; and each limiting block can be used for limiting the corresponding limiting strip. The height of the protective sleeve can be adjusted according to the height of the bolt so that the protective sleeve can be applied to bolts of different heights, high practicability is a