Laser, being intensely bright, highly directional, monochromatic, and coherent, has a wide application in the future of bio-medical science. As a new therapy, laser in clinical practice is mainly used for certain curing effects through its heat and photochemical effects, respectively, obtained from its four properties acting on human organisms to produce certain desired changes. Laser therapy, according to its bio-chemical effects, can be roughly divided into three categories: laser vaporization, laser solidification, and laser stimulation. Clinical practice has proven that each category has its appropriate symptom in all kinds of diseases. Laser therapy is playing a unique part in clinical practice.