The invention relates to the technical field of building levelness monitoring, and discloses a levelness monitoring device and method for a transported building. The device comprises water level gauges and levelling pipes; each water level gauge is provided with scale lines, and the water level gauges and the levelling pipes are both made of a transparent material. The use method comprises the following steps that levelling lines are printed on the side surface of the transported building; every two water level gauges are installed at the two ends of the corresponding levelling line; the zeroscale line of each water level gauge is aligned with the corresponding levelling line; the bottoms of every two water level gauges on the same side surface are communicated with each other through thecorresponding levelling pipe; liquid is injected into the levelling pipes, and the initial liquid level of the liquid is at the zero scale lines of the water level gauges. According to the levelnessmonitoring device, the inclination direction and degree of the building are judged by utilizing the height difference between the liquid surface and the levelling lines, a driver does not need to getoff a vehicle for measurement, the front-rear or left-right height difference of the whole vehicle can be adjusted at any time, it is ensured that the building cannot incline or the inclination angleis within a safety range, the operation is simple, and the use is convenient.