Bolt protective cap

The utility model relates to a bolt protective cap, which is a hollow stair-stepping shell being smaller at the upper part and larger at the lower part; the bolt protective cap comprises a lower part shell covered on a nut and an upper part shell connected with the head of a bolt; wherein stair-stepping round through holes are respectively arranged inside the upper part shell and the lower part shell; the aperture of the lower part shell is more than or equal to the maximum outer diameter of the nut; the upper part shell is provided with internal thread which can be screwed and jointed with the bolt; the outside of the upper part shell takes a prism shape; and the upper part shell and the lower part shell are molded into a whole body by uvioresistant and weather resistant plastics. The bolt protective cap can be firmly fixed on the bolt and can not fall off on a windy day or under the external force of gale, scraping and rubbing of cattle and sheep and the like so as to reduce economic loss and avoid running hidden trouble of associated equipment. Meanwhile, as being made of the uvioresistant and weather resistant plastics, the bolt protective cap can resist the invasion of ultraviolet ray and sand blown by the wind, the service life is prolonged, and the use cost can be reduced.