An explosion-proof junction box belongs to the technical field of wire and cable junction protection. Upper and lower sides of a box body are both provided with cable inlets/outlets. An end surface of a box wall of a box body opening side is step-shaped and located on an inner side, and an end surface lower than a peripheral end surface in height is a box body sealing surface. The width of the box body sealing surface is 2/3 of the thickness of the whole wall, the distance between the peripheral end surface and the box body sealing surface is slightly larger than the thickness of the box body wall. The length and width of a box cover is equal to the length and width of a plane where the box body sealing surface locates. An outer surface of the box cover is provided with cast iron handles. An inner surface of the box cover is of a slightly concave shape, and a protrusion surface around the concave shape is a box cover sealing surface. The box cover sealing surface and the box body sealing surface are the same in width. The explosion-proof junction box is advantageous in that: a position of the sealing surfaces is moved into the box body, an explosion-proof function is enhanced through a secondary seal; and a rubber sealing gasket no longer directly contacts external environment, and the influence of an environmental factor is weakened, so the aging rate is largely reduced or aging rarely occurs, and a safety hidden trouble is eliminated.