Low-level laser therapy is increasingly being used in the medical field, and has apparent advantagessuch as non-invasive, non-toxic side effects compared with those associated with traditional surgery, drugs, and radiationtherapy. It has the positive effects of reducing inflammation, promoting wound healing, nourishing nerves, protectingmuscles, and improving body shape. An in-depth understanding of these mechanisms of action for low-level laser therapycan help to improve the efficacy of the therapy and broaden its range of applications. This article reviews the advances in the application and our understanding of the mechanisms of low-level laser therapy.