Negative pressure bearing plate and assembly type test box

The utility model discloses a negative pressure bearing plate which comprises a bearing plate body and an integrated elastic covering film covering the bearing plate body, the edge of the bearing plate body is provided with a sealing step extending inwards, an I-shaped steel reinforcing rib structure is installed in the bearing plate body, and an assembly type test box is assembled based on the negative pressure bearing plate. Comprising the six negative pressure bearing plates, the sealing steps of every two adjacent negative pressure bearing plates are meshed and matched with each other, due to the reinforcing effect of the I-shaped steel reinforcing rib structures, the negative pressure bearing plates can bear high negative pressure, and after assembly, due to the fact that the adjacent sealing steps are meshed and matched with each other, the sealing effect is good; meanwhile, pressure generated by negative pressure drives the six negative pressure bearing plates to slightly move inwards, the sealing effe