The invention discloses an up-down unsymmetrical double-layer tunnel which comprises a tunnel body. The tunnel body is divided into an upper space and a lower space. The upper space is divided into an upper car running space on the left side and a flue which is placed on the right side and is communicated with the upper car running space. The inner portion of the lower space is divided into an auxiliary space on the left side and a lower car running space which is placed on the right side and is communicated with the flue. Emergency staircases are arranged in the auxiliary space at equal space distance. The tops of the emergency staircases are placed on the lower portion of a car running partitioning plate. A plurality of staircase cover plates corresponding to the emergency staircases are arranged on the car running partitioning plate. By changing the structure arrangement form in the tunnel, a space using mode is optimized, under the condition that structure widening is of no need, up-down layer mutual evacuating can be achieved, ramps are arranged on the two sides of the structure of the up-down layer tunnel, construction land width can be reduced, and the up-down unsymmetrical double-layer tunnel is suitable for road tunneling which is planned to be built in an open cut method when limitation from the construction condition exists, and construction land width has special requirements.