The invention discloses a lifting device convenient to unload sand bags. The lifting device comprises a lifting bag for bearing the sand bags, two first cross beams, and a second cross beam arranged between the two first cross beams; connecting rods are vertically arranged at the two ends of the second cross beam; the lower ends of the connecting rods are rotationally connected with support rods;more than one support rod positioning modules are arranged on the first cross beams; the support rod positioning modules comprise positioning bolts, and two support rod positioning pieces rotationallyconnected to the first cross beams; the support rod positioning pieces consist of first arc positioning pieces and second rectangular positioning pieces connected to the two ends of the first positioning pieces; thread positioning holes are formed in the second positioning pieces below the first positioning pieces; the lifting bag consists of a rectangular bag bottom surface and three bag side surfaces; and the upper ends of the three bag side surfaces are correspondingly connected with the second cross beam and two support rods. The lifting device is special for lifting the sand bags, and has the advantages of quick unloading, power saving and the like.