A lighting system including a powering rod and a first lighting unit is provided. The powering rod is used for providing power. The first lighting unit includes a housing, a light source, an inner ring body and an outer ring body. The light source is disposed inside the housing. The inner ring body, disposed in the housing, has a hollowed portion for receiving the powering rod and is electrically connected to the powering rod. The outer ring body, disposed on the inner ring body fixed to the housing. The outer ring body is capable of rotating with respect to the inner ring body for rotating the housing. When the outer ring body is rotated to a first position, the first lighting unit is in a first lighting state. When the outer ring body is rotated to a second position, the first lighting unit is in a second lighting state.