The invention provides an outdoor blackboard. The outdoor blackboard comprises a writing board frame and a supporting frame. The supporting frame comprises two supporting rods. The two support rods are hinged to the bottom of the writing board frame. A supporting rod accommodating slot is formed in the lower portion of the writing board frame. A first track and a second track are arranged in the writing board frame. A first writing board is arranged in the first track. A second writing board is arranged in the second track. The lengths of the first writing board and the second writing board are the same as the length of the writing board frame. The widths of the first writing board and the second writing board are half of the width of the writing board frame. The first writing board comprises a base plate and a panel, and the second writing board comprises a base plate and a panel. The surface, in contact with the panel, of the base plate is coated with fluorescent materials, and the panel is a glass plate. According to the outdoor blackboard, the base plate of the writing board is coated with fluorescent powder, so that the outdoor blackboard can shine in the dark environment, words, paintings and the like written on the glass plate cover a shining part, and people can clearly identify; and the supporting rods can be folded in the supporting rod accommodating slot, so that theoccupied space is reduced.