The utility model discloses a stair temporary guard bar for building construction protecting. The stair temporary guard bar comprises a blocking frame, a plurality of connecting frames and a handrail rod. The blocking frame is arranged on a top layer floor of a building. The connecting frames are arranged at the crossing portions of upper stairs and lower stairs and at the ground starting end of the stairs. At least two connecting sleeve pipes are arranged at one vertical side of the blocking frame and vertical sides on two sides or one side of each connecting frame. The two ends of the handrail rod are arranged in the connecting sleeve pipes on the corresponding connecting frames or the blocking frame on adjacent layer floors in a penetrating-sleeving mode, and the handrail rod is fixed to the connecting sleeve pipes by the fact that bolts tightly abut against the handrail rod. The stair temporary guard bar is simple in structure, convenient to mount and easy to manufacture, construct and mount, the large amount of long-time lease expense of steel pipes and buckling pieces in the prior art is saved, and construction protecting cost is lowered.