The utility model relates to a shield of novel upturn and downturn door structures of a vehicle-mounted nitrogen making vehicle. The whole shield is cuboid, the left side surface and the right side surface of the shield are both upturn and downturn door structures, and upturn and downturn doors are both multi-chip combined structures, wherein the downturn door is turned to a level state to form a lower stepping structure, and the lower stepping can be positioned via a supporting structure at the bottom of the shield. Compared with the prior art, the upturn and downturn door outer cover of the utility model has the advantages that the whole shield is beautiful, and the shield is rolled up and unfolded rapidly; meanwhile, stepping width is widened, the influence of wind force on shield doors is reduced, and the safety of operating staff is improved.