The invention discloses a painting device for municipal greening. The painting device for municipal greening comprises a base, a movable seat, a fixed shaft, first arc-shaped plates, a bending rail and a slope surface. The bending rail penetrates through the movable seat; sealing pieces for sealing the first arc-shaped plates are arranged at one ends, far away from the fixed shaft, of the two first arc-shaped plates; a storage barrel communicating with the bending rail is connected to the base, and communicates with the other end of the bending rail; and the storage barrel is provided with a sewage pump for pumping a liquid in the storage barrel into the bending rail. Lime water is placed into the storage barrel, the sewage pump pumps the lime water into the top parts of the two first arc-shaped plates, then the lime water can enter the bending rail and further re-flows into the storage barrel along with gravity and along with the bending rail, and during the process, the whole bendingrail is full of the lime water, so that the aim of coating the lime water onto the surface of a tree trunk is achieved, and the painting device for municipal greening has the advantages of convenience, quickness and cost saving.