The invention provides a hot rolling heat holding cover, which relates to an insulated device by a high temperature blank technique. The hot rolling heat holding cover is arranged above a hot blank after tapping, and comprises an arc heat holding cover and an opening-closing mechanism connected to the arc heat holding cover, wherein the opening-closing mechanism controls the arc heat holding coverto open and close. The hot rolling heat holding cover can greatly reduce the heat loss caused by convection and radiation in the process of machining the hot blank, is easy and practical, has low manufacturing cost, and can be widely used in hot rolling procedures for producing rails, steel plates, seamless steel tubes and the like.