A painting system includes a conveyor, a first travel guide rail, a second travel guide rail, a painting robot, and an opener robot. The conveyor is configured to convey in a paint booth an article to be painted. The first travel guide rail is provided at a side of the conveyor to extend along the conveyor. The second travel guide rail is provided at a side of the conveyor to extend along the conveyor above the first travel guide rail. The painting robot is mounted on the first travel guide rail to be movable along the first travel guide rail. The opener robot is mounted on the second travel guide rail to be movable along the second travel guide rail. The painting robot and the opener robot are movable along the first travel guide rail and the second travel guide rail respectively without interfering with each other.