The paper cup collecting and stacking system comprises a main base, a main support is arranged on one side of the top face of the main base, a falling mechanism is arranged on the upper portion of the support, a falling stabilizing opening is formed in one side of the main support, a stacking mechanism is arranged on the other side of the main base, and the lower portion of the stacking mechanism is connected with a driving mechanism in an engaged mode. According to the paper cup stacking device, inverted paper cups are aligned through the inverted aligning unit, the falling paper cups are stacked through the stacking unit in the stacking mechanism, when the stacking height reaches the set height, an inductor is triggered, and therefore the driving mechanism is started to drive the stacking mechanism to rotate, and the paper cups are stacked through the stacking unit in the stacking mechanism. According to the paper cup stacking device, the next stacking unit continues to conduct stacking, it is guaranteed that the number of each pile of paper cups is the same, meanwhile, the paper cups stacked in the previous stacking unit are pushed out through cooperation of the cam shaft and the stacking base, manual taking is convenient, and the manual discharging efficiency is greatly improved.