The invention relates to the technical field of plant tissue culture, in particular to a circular plant tissue culture box, which comprises an upper cover and a base seat, wherein the upper cover andthe base seat are connected in a rotary manner, and a limiting device, which is matched with the upper cover and the base seat, limits the rotation angle and aligns positions, is arranged at the jointof the upper cover and the base seat. By arranging the limiting device at the joint of the upper cover and the base seat, a convex is designed on internal threads of the upper cover at the corresponding position of the limiting device, a notch is designed on the threads at the corresponding position of the base seat, the indicating position is correspondingly switched to clamp the upper cover andthe base seat only by rotating less than 180 degrees, and thus the number of rotation of the threads at the joint between the cover and the base seat is decreased.