The invention discloses a hydraulic automatic tank aligning crossing device for a multilayer tank cage. The device comprises a push plate bottom frame, swing table rail grooves, a push plate front roller, a push plate rear roller and a drive device; the swing table rail grooves are formed in the two sides of the bottom of a well building stair platform in parallel and are fixedly connected with the two sides of the bottom of the well building stair platform; a mandrel of the push plate front roller and/or a mandrel of the push plate rear roller are/is fixedly arranged on the push plate bottom frame of a frame structure and matched with the push plate rail grooves; the push plate bottom frame and the push plate front roller or the push plate rear roller are connected with the drive device so as to push the push plate bottom frame to move along the swing table rail grooves in a back-and-forth manner; the push plate bottom frame moving along the rail grooves is arranged at the bottom of the well building stair platform, the drive device pushes the push plate bottom frame to be aligned with or retracted from a two-layer platform of the tank cage, and therefore the aim that a person and materials can get on and off the tank cage from the first layer and the second layer at the same time is achieved, that is, a worker can conveniently enter in and go out of the cage, and the secondary tank aligning time is shortened. Therefore, the device has the beneficial effects of being simple in structure, rapid and convenient to operate, high in vertical shaft work efficiency, safe and reliable.