The invention provides a single-shoulder cross-body-type protection backpack capable of being worn rapidly for solving the problems of a current protection device that the wearing speed is low; the professionality is high; and use and carrying are inconvenient. The single-shoulder cross-body-type protection backpack comprises a backpack and one or more protection layers, and the protection layers mainly comprise a chest part protection layer, a back part protection layer, a heart part protection layer and auxiliary connection components thereof. The backpack is provided with a storage space for accommodating objects; the backpack is further provided with an interlayer; the fore-chest part protection layer, the back part protection layer, the heart part protection layer and the auxiliary connection components thereof are accommodated in the interlayer; and during use, the backpack is moved to the fore-chest rapidly from the rear side of the body, and the back part protection layer can be rapidly unfolded to the back in 1-3 seconds. By utilizing the single-shoulder cross-body-type protection backpack, the chest, the back, the heart and other body critical parts can be effectively protected with the highest speed when encountering attack; and fire-proof, drowning-proof, warm-keeping and safe-warning functions and the like can be realized by changing the materials of the protection layers.