The present invention discloses a flameproof box hydraulic test device, belonging to the field of the instrument and apparatus field. As regards hydraulic test devices utilized in flameproof box production enterprises in the prior art, the box body total rigidities of middle-sized or large-size hydraulic test devices with single side sizes being larger than 700mm are decreased with the improved sized, and the box bodies are deformed or destroyed caused by slightly inappropriate pressure mechanisms. The flameproof box hydraulic test device comprises a frame, a guide rail, a flat and a hydraulic cylinder; and the guide rail vertically and/or horizontally installed on the frame, the flat being parallel with the guide rail is installed on the guide rail and is able to move along with the guide rail, at least five hydraulic cylinders being perpendicular to the flat are installed on the flat, and each hydraulic cylinder is uniformly arranged with the box cover of the flameproof box so that the body cover obtains even pressure. Through replacing auxiliary clamps, the flameproof box hydraulic test device is able to be suitable for flameproof boxes with different sizes and different shapes such as a rectangular, a circle and the like.