Disclosed are a support unit and a floor plate. The support unit includes a first plate and a second plate which are spaced apart from each other, one end of the first plate is provided with a plurality of first ring walls at intervals, one end of second plate facing the first plate is provided with a plurality of second ring walls at intervals, the plurality of second ring walls are arranged corresponding to the plurality of first ring walls, each of the second ring walls is sleeved outside and matched with a respective one of the first ring walls to form a support structure that supports the first plate and the second plate.