A plasma system for generating a plasma is generated. The plasma system includes a tube, a positive electrode and a negative electrode. The tube has a plasma jet opening, a first end surface and a second end surface. The plasma jet opening penetrates the wall of the tube. The plasma passes through the plasma jet opening and is emitted to the outside of the tube. The positive electrode has a side surface facing and adjacent to the tube. The negative electrode is separated from the positive electrode by a first predetermined distance. The negative electrode has a negative electrode side surface facing and adjacent to the tube. The first positive electrode and the first negative electrode are disposed between the first end surface and the second end surface, and a portion of the plasma jet opening is disposed between the positive electrode and the negative electrode.